Stinky thermal paste emits acidic vapors, corrodes copper, 'glues' heatsinks to processors, and permanently damages coolers - SGT-4 TIM is a chemically reactive blend, finds investigation

Some thermal pastes are good for air cooling, others for liquid cooling, some are generally efficient, others are not. But as our colleague Igor Wallosek discovered, there is a thermal paste that stinks and damages coolers. That thermal paste — Amech (Aimac) SGT-4 made in South Korea — appears to be quite popular in online stores around the world because it is cheap and gets favorable user reviews. Yet, SGT-4 appears to be a chemically reactive blend that stinks due to acidic vapors, permanently damages CPUs and coolers with pitting from corrosion, and causes coolers to glue to the chip. The TIM also doesn't meet its thermal ratings due to the pitting.

SGT-4 (not among the best thermal greases that Tom's Hardware has tested) is based on PMDS; however, chemical testing and user evidence indicate that it is not a standard silicone-based thermal paste, as it adds a reactive acetoxy-curing RTV silicone, a substance that seems to release acetic acid when it contacts moisture, based on Igor's findings. This additive — likely methyltriacetoxysilane, according to Igor's Lab — was apparently used to make the grease cohesive and adhesive when applied at thin bond lines, but its reaction produces acidic vapors that cause metal oxidation and the smell of vinegar. 

During operation, the acetic acid gradually corrodes copper surfaces, causes pitting and discoloration, and glues surfaces together, according to both Igor and his readers. Although the substance glues the cooler to the CPU, Igor Lab's measurements found that thermal conductivity was far below the manufacturer's claims, probably due to pitting (called 'ant nest corrosion') caused by the acid. Normally, thermal greases are applied to fill in the imperfections of the surfaces of the cooler and the cooled system, thus enhancing cooling performance. This appears not to be the case with the SGT-4, as instead of filling the voids, it creates new ones.

Community posts on Quasarzone — a South Korean website — confirm a host of problems, such as erased CPU markings, copper discoloration, and pitting on copper. Despite the fact that Amech prefers to be an incognito 'brand' with no website, users from South Korea have found a way to contact it. 

The manufacturer's reaction was not exactly supportive: instead of addressing the evidence, Amech representatives issued personal insults, dismissed the findings as baseless, and insisted the product complied with RoHS and REACH environmental standards that prove that the grease does not contain any hazardous substances. Meanwhile, such certifications are irrelevant to metal reactivity or being precursors of hazardous substances, especially under normal usage conditions.

To make matters even worse, the Amech reps repeatedly referred to Igor's unveilings as 'a person from Germany' to discredit the source while avoiding any technical rebuttal. They have never disclosed the paste's composition either. As a result, by mid-October, trust in the company had collapsed completely among the community.

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