SlideShare a Scribd company logo
1 of 7
Download to read offline
Innodisk Corporation. All Rights Reserved. 1
Removing the Threat of
Sulfuration to DRAM Modules
White Paper
Executive Summary
Pollution from fossil fuels and volcanic activity are the
main sources of sulfur contaminants in the air. Sulfur in
form of hydrogen sulfide will react with silver located
in DRAM resistors in a corrosive reaction that lowers
conductivity and eventually causes module failure.
A protective layer can be added to ensure that the silver
does not come into contact with hydrogen sulfide, thus
preventing corrosion. Alternatively, the silver alloy can be
altered to increase sulfur resistance.
Tests using the ASTM B809-95 standard show that
switching to anti-sulfuration resistors provides full
protection against hydrogen sulfide in the air.
Innodisk Corporation. All Rights Reserved. 2
Background How does silver corrode?
Elemental/pure silver is relatively stable and non-reactive in air. However,
hydrogen sulfide gas will cause silver to oxidize, even when only present
in low quantities. This is a form of corrosion (also called tarnishing) that
leaves a thin layer of black silver sulfide on the surface of the metal, and can
typically be observed on silverware and silver coins that have been exposed
to sulfides in water or air.
Introduction
Embedded operators are facing increasing difficulty with high sulfur content in their surroundings.
This can be attributed to the trends of IoT and edge computing where devices are moving out into
the field where environmental risks are greater.
Sulfur contamination will cause corrosion damage to DRAM modules and other sensitive
equipment. DRAM resistors use silver due to its high conductivity and stability. It is, however,
susceptible to corrosion from sulfide, especially in the form of hydrogen sulfide gas. Once the silver
corrodes, it loses all conductivity. This will eventually lead to module failure and consequently the
whole system crashing.
Hydrogen sulfide gas exists in minuscule amounts in the atmosphere, but elevated levels are found
in areas with volcanic activity and areas with pollution from fossil fuels.
Other than the more obvious scenarios where one can encounter sulfur contamination, it is also
seen as a hidden danger in data centers. Data center air intakes can carry contaminants into the
building, and urban areas will have higher hydrogen sulfide levels due to traffic and other forms of
pollution.
Protecting DRAM modules can be done with different methods but the main two contenders are:
1. Adding a Protective Layer across the sensitive area
2. Replacing the silver with a more resistant alloy
Furthermore, DRAM modules can be tested for sulfur resistance through the ASTM B809-95
testing standard.
This paper will expound on the problem of sulfuration and further discuss the two main methods of
solving the issue, as well as how to verify the quality of the sulfuration protection.
Innodisk Corporation. All Rights Reserved. 3
DRAM Resistors
The resistors used on DRAM PCBs (Printed Circuit Board) are called SMD
resistors (Surface Mount Device). These resistors have an electrode placed
on top of a ceramic substrate (see figure 1). The electrode has to be a good
conductor of electricity and is placed above the non-conducting ceramic
material.
The ASTM B809-95 Testing Standard
ASTM International, formerly known as The American Society for Testing
and Materials, provides testing standards on a world-wide basis. The most
suitable standard for testing anti-sulfuration is ASTM B809-95, which is also
the most commonly known among suppliers of resitors. This standard is also
called Standard Test Method for Porosity in Metallic Coatings by Humid Sulfur
Vapor (“Flowers-of-Sulfur”) and is designed to recreate a high-humidity, high-
temperature environment with elevated hydrogen sulfide levels.
Where silver (Ag) is oxidized and sulfur (S) is reduced to create silver sulfide
(Ag2S). The hydrogen (H) from the hydrogen sulfide (H2S) forms hydrogen gas
(H2). Salts and higher levels of humidity will act as catalysts and increase the
rate of the reaction.
Pure silver is one of the best conductors of electricity, but once it oxidizes
and forms silver sulfide it loses all conductivity. This means that silver that is
in contact with hydrogen sulfide will steadily lose conductivity as long as the
reaction is allowed to happen.
Figure 1: DRAM resistor showing electrode above the ceramic substrate
The balanced chemical reaction is as follows:
Innodisk Corporation. All Rights Reserved. 4
Challenges
Solutions
The main issue with sulfur contamination and DRAM modules is when the
silver electrode comes into contact with air holding higher levels of hydrogen
sulfide. Once the hydrogen sulfide gas starts oxidizing the silver, conductivity
will slowly decrease until the module eventually fails.
The sulfuration process can be observed by noticing a color shift as seen in
the picture below.
Protective Layer
The protective layer solution is simple and straight-forward; a layer of
protective film is added around the electrode to isolate it from air contact
and potential sulfuration (see figure 4). The layer also prevents any gas
diffusion, as even a tiny amount of hydrogen sulfide particle is enough to
affect the electrode. This method is also relatively inexpensive and easy to
implement.
DRAM modules are suspended above a container of pure sulfur and
potassium nitrate (KNO3) that is continuously releasing hydrogen sulfide gas.
The test described in this paper was run significantly longer than stipulated
by the testing procedure, thus ensuring that all susceptible metals that are in
contact with the air will have undergone corrosion.
Picture 1: Resistors changing colors after test completion on standard DRAM module
Figure 2: Basic setup of ASTM B809-95
Innodisk Corporation. All Rights Reserved. 5
Altering Electrode Alloy
The issue of sulfuration can be addressed by altering the silver alloy used in
the electrode. This is usually done by increasing the amount of palladium in
the alloy. Palladium is less reactive compared to silver and can form alloys
that are sulfur-resistant.
However, palladium is also significantly more expensive than silver, which
means this solution will be more costly than the above mentioned protective
layer.
Testing of DRAM Using Anti-Sulfuration Resistor
Testing was conducted on several modules fitted with anti-sulfuration
resistors (see below) according to the ASTM B809-95 standard.
Figure 3: A standard resistor (left) and a resistor with an added protective layer
(right) marked in yellow
Picture 2: Testing of DRAM modules fitted with anti-sulfuration resistors
Innodisk Corporation. All Rights Reserved. 6
Protecting DRAM modules and other sensitive components is essential as
the number of devices around us grows and the risk of sulfur contamination
increases. Sulfur can be an unaccounted risk factor in many embedded
environments and can cause significant damage if ignored.
Solutions are, however, readily available. Adding a protective layer inside the
resistors is easily done at a comparatively low cost. While altering the silver
alloy to increase sulfur resistance is a viable solution, it is also associated
with a higher cost increase.
Every operator facing the risk of sulfuration should take the necessary steps
to protect memory modules as any increase in cost will be far outweighed by
the consequences of module failure.
Conclusion
Picture 3: DRAM anti-sulfuration resistors unaffected after sulfuration test
All modules showed no signs of tarnishing after having completed the testing
procedure. The resistors kept their original white-gray coloring indicating no
or indistinguishable levels of corrosion.
Copyright © June 2018 Innodisk Corporation. All rights reserved. Innodisk is a trademark of Innodisk Corporation,
registered in the United States and other countries. Other brand names mentioned herein are for identification
purposes only and may be the trademarks of their respective owner(s).
Innodisk Corporation
5F., NO. 237, Sec. 1, Datong Rd., Xizhi Dist., New Tapei City, 221, Taiwan
Tel : +886-2-7703-3000
Fax : +886-2-7703-3555
E-Mail : sales@innodisk.com
Website : www.innodisk.com
The Innodisk Solution
Anti-Sulfuration added to all DDR4 DRAM Modules
Extended Longevity
The robust anti-sulfuration design greatly increases the modules longevity in
harsh environments
Free-of-Cost Upgrade
All Innodisk DDR4 modules will be upgraded without any added cost to
include robust anti-sulfuration measures
Lower Total Cost of Ownership
Increased durability ensures longer sustained use without the need for
maintenance or replacement

More Related Content

What's hot

Weld Purging ~ Corrosion Problems in Stainless Steel by Welding
Weld Purging ~ Corrosion Problems in Stainless Steel by WeldingWeld Purging ~ Corrosion Problems in Stainless Steel by Welding
Weld Purging ~ Corrosion Problems in Stainless Steel by WeldingRon Sewell
 
Corrosion Behaviour of 6061 Al-SiC Composites in KOH Medium
Corrosion Behaviour of 6061 Al-SiC Composites in KOH MediumCorrosion Behaviour of 6061 Al-SiC Composites in KOH Medium
Corrosion Behaviour of 6061 Al-SiC Composites in KOH MediumEditor IJCATR
 
Corrosion Consulting
Corrosion ConsultingCorrosion Consulting
Corrosion ConsultingSteve1954
 
ME306 group project
ME306 group projectME306 group project
ME306 group projectguestcdbd15d
 
I Got 99 Problems But Welding Ain't One
I Got 99 Problems But Welding Ain't One I Got 99 Problems But Welding Ain't One
I Got 99 Problems But Welding Ain't One Ron Sewell
 
Corrosion Sl Part Three
Corrosion Sl Part ThreeCorrosion Sl Part Three
Corrosion Sl Part ThreeSteve1954
 
Material and corrosion in petroleum
Material and corrosion in petroleumMaterial and corrosion in petroleum
Material and corrosion in petroleumMalek Exchange
 
H144247
H144247H144247
H144247irjes
 
The inhibition effect of hydralazine hydrochloride on corrosion of mild steel...
The inhibition effect of hydralazine hydrochloride on corrosion of mild steel...The inhibition effect of hydralazine hydrochloride on corrosion of mild steel...
The inhibition effect of hydralazine hydrochloride on corrosion of mild steel...Premier Publishers
 
180831 nawtec__inconel overlay
180831  nawtec__inconel overlay180831  nawtec__inconel overlay
180831 nawtec__inconel overlayRobert Morin
 
Corrosion inhibition of mild steel by TPPMB in HCl solution (Khayat)[1]
Corrosion inhibition of mild steel by TPPMB in HCl solution (Khayat)[1]Corrosion inhibition of mild steel by TPPMB in HCl solution (Khayat)[1]
Corrosion inhibition of mild steel by TPPMB in HCl solution (Khayat)[1]Ibrahim Abdel-Rahman
 
Corrosion inspection in oil and gas pipeline
Corrosion inspection in oil and gas pipelineCorrosion inspection in oil and gas pipeline
Corrosion inspection in oil and gas pipelinedia_dean
 
Welding
WeldingWelding
Weldingodorox
 
A study of the corrosion behavior of magnesium and its alloys
A study of the corrosion behavior of magnesium and its alloysA study of the corrosion behavior of magnesium and its alloys
A study of the corrosion behavior of magnesium and its alloysAlexander Decker
 
Exothermic welding powder
Exothermic welding powderExothermic welding powder
Exothermic welding powderUjjwal Shah
 
Compounds selector-guide
Compounds selector-guideCompounds selector-guide
Compounds selector-guidemrittika01
 

What's hot (18)

Weld Purging ~ Corrosion Problems in Stainless Steel by Welding
Weld Purging ~ Corrosion Problems in Stainless Steel by WeldingWeld Purging ~ Corrosion Problems in Stainless Steel by Welding
Weld Purging ~ Corrosion Problems in Stainless Steel by Welding
 
Corrosion Behaviour of 6061 Al-SiC Composites in KOH Medium
Corrosion Behaviour of 6061 Al-SiC Composites in KOH MediumCorrosion Behaviour of 6061 Al-SiC Composites in KOH Medium
Corrosion Behaviour of 6061 Al-SiC Composites in KOH Medium
 
Corrosion Consulting
Corrosion ConsultingCorrosion Consulting
Corrosion Consulting
 
ME306 group project
ME306 group projectME306 group project
ME306 group project
 
I Got 99 Problems But Welding Ain't One
I Got 99 Problems But Welding Ain't One I Got 99 Problems But Welding Ain't One
I Got 99 Problems But Welding Ain't One
 
Corrosion Sl Part Three
Corrosion Sl Part ThreeCorrosion Sl Part Three
Corrosion Sl Part Three
 
5208 chap 09
5208 chap 095208 chap 09
5208 chap 09
 
Material and corrosion in petroleum
Material and corrosion in petroleumMaterial and corrosion in petroleum
Material and corrosion in petroleum
 
H144247
H144247H144247
H144247
 
The inhibition effect of hydralazine hydrochloride on corrosion of mild steel...
The inhibition effect of hydralazine hydrochloride on corrosion of mild steel...The inhibition effect of hydralazine hydrochloride on corrosion of mild steel...
The inhibition effect of hydralazine hydrochloride on corrosion of mild steel...
 
180831 nawtec__inconel overlay
180831  nawtec__inconel overlay180831  nawtec__inconel overlay
180831 nawtec__inconel overlay
 
Ijmet 10 01_110
Ijmet 10 01_110Ijmet 10 01_110
Ijmet 10 01_110
 
Corrosion inhibition of mild steel by TPPMB in HCl solution (Khayat)[1]
Corrosion inhibition of mild steel by TPPMB in HCl solution (Khayat)[1]Corrosion inhibition of mild steel by TPPMB in HCl solution (Khayat)[1]
Corrosion inhibition of mild steel by TPPMB in HCl solution (Khayat)[1]
 
Corrosion inspection in oil and gas pipeline
Corrosion inspection in oil and gas pipelineCorrosion inspection in oil and gas pipeline
Corrosion inspection in oil and gas pipeline
 
Welding
WeldingWelding
Welding
 
A study of the corrosion behavior of magnesium and its alloys
A study of the corrosion behavior of magnesium and its alloysA study of the corrosion behavior of magnesium and its alloys
A study of the corrosion behavior of magnesium and its alloys
 
Exothermic welding powder
Exothermic welding powderExothermic welding powder
Exothermic welding powder
 
Compounds selector-guide
Compounds selector-guideCompounds selector-guide
Compounds selector-guide
 

Similar to [White Paper] Removing the Threat of Sulfuration to DRAM Modules

Canada Metal: Lead sheet metal for nuclear shielding, Construction
Canada Metal: Lead sheet metal for nuclear shielding, ConstructionCanada Metal: Lead sheet metal for nuclear shielding, Construction
Canada Metal: Lead sheet metal for nuclear shielding, Constructioncanadametal
 
Use of Sheet Lead as the Protective Shielding
Use of Sheet Lead as the Protective ShieldingUse of Sheet Lead as the Protective Shielding
Use of Sheet Lead as the Protective Shieldingcanadametal
 
Corrosion and corrosion inhibition of copper alloys in acid medium
Corrosion and corrosion inhibition of copper alloys in acid mediumCorrosion and corrosion inhibition of copper alloys in acid medium
Corrosion and corrosion inhibition of copper alloys in acid mediummohammed rida
 
Aluminium Corrosion Alodine Protective Coating
Aluminium Corrosion Alodine Protective CoatingAluminium Corrosion Alodine Protective Coating
Aluminium Corrosion Alodine Protective CoatingFernandoVicente25
 
Loss of corrosion and prevention of corrosion
Loss of corrosion and prevention of corrosionLoss of corrosion and prevention of corrosion
Loss of corrosion and prevention of corrosionAl Fahad
 
Guide Lines For Duplex Stainless Steel Welding
Guide Lines For Duplex Stainless Steel WeldingGuide Lines For Duplex Stainless Steel Welding
Guide Lines For Duplex Stainless Steel Weldingzhuangxu1983
 
Inconel 825
Inconel  825Inconel  825
Inconel 8251078S2
 
Phosphating and chromating
Phosphating and chromatingPhosphating and chromating
Phosphating and chromatingAbishek Arumugam
 
THERMAL SPRAY (TiO2) COATING - For Automobile Engine Pistons
THERMAL SPRAY (TiO2) COATING - For Automobile Engine PistonsTHERMAL SPRAY (TiO2) COATING - For Automobile Engine Pistons
THERMAL SPRAY (TiO2) COATING - For Automobile Engine PistonsPrasath viky
 
AMINE SERVICE.pdf
AMINE SERVICE.pdfAMINE SERVICE.pdf
AMINE SERVICE.pdfadelzahed1
 
Corrosion Inhibition of Carbon Steel in Chloride and Sulfate Solutions
Corrosion Inhibition of Carbon Steel in Chloride and Sulfate SolutionsCorrosion Inhibition of Carbon Steel in Chloride and Sulfate Solutions
Corrosion Inhibition of Carbon Steel in Chloride and Sulfate SolutionsIJERA Editor
 
International Journal of Engineering Research and Development
International Journal of Engineering Research and DevelopmentInternational Journal of Engineering Research and Development
International Journal of Engineering Research and DevelopmentIJERD Editor
 
Corrosion resistant nickel alloys behavior
Corrosion resistant nickel alloys behaviorCorrosion resistant nickel alloys behavior
Corrosion resistant nickel alloys behaviorHeanjia Alloys
 
Corrosion engineering
Corrosion engineeringCorrosion engineering
Corrosion engineeringAtul Shinde
 
Fabio scatiggio understanding and management of sulphur corrosion form insu...
Fabio scatiggio   understanding and management of sulphur corrosion form insu...Fabio scatiggio   understanding and management of sulphur corrosion form insu...
Fabio scatiggio understanding and management of sulphur corrosion form insu...sarah7887
 
Cambridge NanoTech ALD Tutorial
Cambridge NanoTech ALD TutorialCambridge NanoTech ALD Tutorial
Cambridge NanoTech ALD TutorialCambridgeNano
 

Similar to [White Paper] Removing the Threat of Sulfuration to DRAM Modules (20)

Canada Metal: Lead sheet metal for nuclear shielding, Construction
Canada Metal: Lead sheet metal for nuclear shielding, ConstructionCanada Metal: Lead sheet metal for nuclear shielding, Construction
Canada Metal: Lead sheet metal for nuclear shielding, Construction
 
Use of Sheet Lead as the Protective Shielding
Use of Sheet Lead as the Protective ShieldingUse of Sheet Lead as the Protective Shielding
Use of Sheet Lead as the Protective Shielding
 
Corrosion and corrosion inhibition of copper alloys in acid medium
Corrosion and corrosion inhibition of copper alloys in acid mediumCorrosion and corrosion inhibition of copper alloys in acid medium
Corrosion and corrosion inhibition of copper alloys in acid medium
 
Aluminium Corrosion Alodine Protective Coating
Aluminium Corrosion Alodine Protective CoatingAluminium Corrosion Alodine Protective Coating
Aluminium Corrosion Alodine Protective Coating
 
Loss of corrosion and prevention of corrosion
Loss of corrosion and prevention of corrosionLoss of corrosion and prevention of corrosion
Loss of corrosion and prevention of corrosion
 
Guide Lines For Duplex Stainless Steel Welding
Guide Lines For Duplex Stainless Steel WeldingGuide Lines For Duplex Stainless Steel Welding
Guide Lines For Duplex Stainless Steel Welding
 
Inconel 825
Inconel  825Inconel  825
Inconel 825
 
Phosphating and chromating
Phosphating and chromatingPhosphating and chromating
Phosphating and chromating
 
ALD Tutorial
ALD Tutorial ALD Tutorial
ALD Tutorial
 
ALD Tutorial
ALD TutorialALD Tutorial
ALD Tutorial
 
THERMAL SPRAY (TiO2) COATING - For Automobile Engine Pistons
THERMAL SPRAY (TiO2) COATING - For Automobile Engine PistonsTHERMAL SPRAY (TiO2) COATING - For Automobile Engine Pistons
THERMAL SPRAY (TiO2) COATING - For Automobile Engine Pistons
 
AMINE SERVICE.pdf
AMINE SERVICE.pdfAMINE SERVICE.pdf
AMINE SERVICE.pdf
 
Cswip 111 of painting
Cswip 111 of paintingCswip 111 of painting
Cswip 111 of painting
 
Corrosion Inhibition of Carbon Steel in Chloride and Sulfate Solutions
Corrosion Inhibition of Carbon Steel in Chloride and Sulfate SolutionsCorrosion Inhibition of Carbon Steel in Chloride and Sulfate Solutions
Corrosion Inhibition of Carbon Steel in Chloride and Sulfate Solutions
 
International Journal of Engineering Research and Development
International Journal of Engineering Research and DevelopmentInternational Journal of Engineering Research and Development
International Journal of Engineering Research and Development
 
Corrosion resistant nickel alloys behavior
Corrosion resistant nickel alloys behaviorCorrosion resistant nickel alloys behavior
Corrosion resistant nickel alloys behavior
 
Corrosion engineering
Corrosion engineeringCorrosion engineering
Corrosion engineering
 
Fabio scatiggio understanding and management of sulphur corrosion form insu...
Fabio scatiggio   understanding and management of sulphur corrosion form insu...Fabio scatiggio   understanding and management of sulphur corrosion form insu...
Fabio scatiggio understanding and management of sulphur corrosion form insu...
 
NCECA 2014: William Carty
NCECA 2014: William CartyNCECA 2014: William Carty
NCECA 2014: William Carty
 
Cambridge NanoTech ALD Tutorial
Cambridge NanoTech ALD TutorialCambridge NanoTech ALD Tutorial
Cambridge NanoTech ALD Tutorial
 

[White Paper] Removing the Threat of Sulfuration to DRAM Modules

  • 1. Innodisk Corporation. All Rights Reserved. 1 Removing the Threat of Sulfuration to DRAM Modules White Paper Executive Summary Pollution from fossil fuels and volcanic activity are the main sources of sulfur contaminants in the air. Sulfur in form of hydrogen sulfide will react with silver located in DRAM resistors in a corrosive reaction that lowers conductivity and eventually causes module failure. A protective layer can be added to ensure that the silver does not come into contact with hydrogen sulfide, thus preventing corrosion. Alternatively, the silver alloy can be altered to increase sulfur resistance. Tests using the ASTM B809-95 standard show that switching to anti-sulfuration resistors provides full protection against hydrogen sulfide in the air.
  • 2. Innodisk Corporation. All Rights Reserved. 2 Background How does silver corrode? Elemental/pure silver is relatively stable and non-reactive in air. However, hydrogen sulfide gas will cause silver to oxidize, even when only present in low quantities. This is a form of corrosion (also called tarnishing) that leaves a thin layer of black silver sulfide on the surface of the metal, and can typically be observed on silverware and silver coins that have been exposed to sulfides in water or air. Introduction Embedded operators are facing increasing difficulty with high sulfur content in their surroundings. This can be attributed to the trends of IoT and edge computing where devices are moving out into the field where environmental risks are greater. Sulfur contamination will cause corrosion damage to DRAM modules and other sensitive equipment. DRAM resistors use silver due to its high conductivity and stability. It is, however, susceptible to corrosion from sulfide, especially in the form of hydrogen sulfide gas. Once the silver corrodes, it loses all conductivity. This will eventually lead to module failure and consequently the whole system crashing. Hydrogen sulfide gas exists in minuscule amounts in the atmosphere, but elevated levels are found in areas with volcanic activity and areas with pollution from fossil fuels. Other than the more obvious scenarios where one can encounter sulfur contamination, it is also seen as a hidden danger in data centers. Data center air intakes can carry contaminants into the building, and urban areas will have higher hydrogen sulfide levels due to traffic and other forms of pollution. Protecting DRAM modules can be done with different methods but the main two contenders are: 1. Adding a Protective Layer across the sensitive area 2. Replacing the silver with a more resistant alloy Furthermore, DRAM modules can be tested for sulfur resistance through the ASTM B809-95 testing standard. This paper will expound on the problem of sulfuration and further discuss the two main methods of solving the issue, as well as how to verify the quality of the sulfuration protection.
  • 3. Innodisk Corporation. All Rights Reserved. 3 DRAM Resistors The resistors used on DRAM PCBs (Printed Circuit Board) are called SMD resistors (Surface Mount Device). These resistors have an electrode placed on top of a ceramic substrate (see figure 1). The electrode has to be a good conductor of electricity and is placed above the non-conducting ceramic material. The ASTM B809-95 Testing Standard ASTM International, formerly known as The American Society for Testing and Materials, provides testing standards on a world-wide basis. The most suitable standard for testing anti-sulfuration is ASTM B809-95, which is also the most commonly known among suppliers of resitors. This standard is also called Standard Test Method for Porosity in Metallic Coatings by Humid Sulfur Vapor (“Flowers-of-Sulfur”) and is designed to recreate a high-humidity, high- temperature environment with elevated hydrogen sulfide levels. Where silver (Ag) is oxidized and sulfur (S) is reduced to create silver sulfide (Ag2S). The hydrogen (H) from the hydrogen sulfide (H2S) forms hydrogen gas (H2). Salts and higher levels of humidity will act as catalysts and increase the rate of the reaction. Pure silver is one of the best conductors of electricity, but once it oxidizes and forms silver sulfide it loses all conductivity. This means that silver that is in contact with hydrogen sulfide will steadily lose conductivity as long as the reaction is allowed to happen. Figure 1: DRAM resistor showing electrode above the ceramic substrate The balanced chemical reaction is as follows:
  • 4. Innodisk Corporation. All Rights Reserved. 4 Challenges Solutions The main issue with sulfur contamination and DRAM modules is when the silver electrode comes into contact with air holding higher levels of hydrogen sulfide. Once the hydrogen sulfide gas starts oxidizing the silver, conductivity will slowly decrease until the module eventually fails. The sulfuration process can be observed by noticing a color shift as seen in the picture below. Protective Layer The protective layer solution is simple and straight-forward; a layer of protective film is added around the electrode to isolate it from air contact and potential sulfuration (see figure 4). The layer also prevents any gas diffusion, as even a tiny amount of hydrogen sulfide particle is enough to affect the electrode. This method is also relatively inexpensive and easy to implement. DRAM modules are suspended above a container of pure sulfur and potassium nitrate (KNO3) that is continuously releasing hydrogen sulfide gas. The test described in this paper was run significantly longer than stipulated by the testing procedure, thus ensuring that all susceptible metals that are in contact with the air will have undergone corrosion. Picture 1: Resistors changing colors after test completion on standard DRAM module Figure 2: Basic setup of ASTM B809-95
  • 5. Innodisk Corporation. All Rights Reserved. 5 Altering Electrode Alloy The issue of sulfuration can be addressed by altering the silver alloy used in the electrode. This is usually done by increasing the amount of palladium in the alloy. Palladium is less reactive compared to silver and can form alloys that are sulfur-resistant. However, palladium is also significantly more expensive than silver, which means this solution will be more costly than the above mentioned protective layer. Testing of DRAM Using Anti-Sulfuration Resistor Testing was conducted on several modules fitted with anti-sulfuration resistors (see below) according to the ASTM B809-95 standard. Figure 3: A standard resistor (left) and a resistor with an added protective layer (right) marked in yellow Picture 2: Testing of DRAM modules fitted with anti-sulfuration resistors
  • 6. Innodisk Corporation. All Rights Reserved. 6 Protecting DRAM modules and other sensitive components is essential as the number of devices around us grows and the risk of sulfur contamination increases. Sulfur can be an unaccounted risk factor in many embedded environments and can cause significant damage if ignored. Solutions are, however, readily available. Adding a protective layer inside the resistors is easily done at a comparatively low cost. While altering the silver alloy to increase sulfur resistance is a viable solution, it is also associated with a higher cost increase. Every operator facing the risk of sulfuration should take the necessary steps to protect memory modules as any increase in cost will be far outweighed by the consequences of module failure. Conclusion Picture 3: DRAM anti-sulfuration resistors unaffected after sulfuration test All modules showed no signs of tarnishing after having completed the testing procedure. The resistors kept their original white-gray coloring indicating no or indistinguishable levels of corrosion.
  • 7. Copyright © June 2018 Innodisk Corporation. All rights reserved. Innodisk is a trademark of Innodisk Corporation, registered in the United States and other countries. Other brand names mentioned herein are for identification purposes only and may be the trademarks of their respective owner(s). Innodisk Corporation 5F., NO. 237, Sec. 1, Datong Rd., Xizhi Dist., New Tapei City, 221, Taiwan Tel : +886-2-7703-3000 Fax : +886-2-7703-3555 E-Mail : sales@innodisk.com Website : www.innodisk.com The Innodisk Solution Anti-Sulfuration added to all DDR4 DRAM Modules Extended Longevity The robust anti-sulfuration design greatly increases the modules longevity in harsh environments Free-of-Cost Upgrade All Innodisk DDR4 modules will be upgraded without any added cost to include robust anti-sulfuration measures Lower Total Cost of Ownership Increased durability ensures longer sustained use without the need for maintenance or replacement