Hastelloy

A brand name for a group of nickel alloys whose main components are Ni-Mo. It is important as an alloy with excellent hydrochloric acid resistance and as a heat-resistant alloy. There are types B, C, D, F, X, etc., depending on the alloy components. B contains 28% Mo by mass and 5% Fe by mass, and is resistant to hydrochloric acid of all concentrations up to the boiling point, as well as hydrogen chloride gas and sulfuric acid, but is attacked by nitric acid. It also has excellent heat resistance, and in oxidizing atmospheres, Mo oxidizes and evaporates, so it is limited to temperatures below 760°C, but in reducing atmospheres it can be used at even higher temperatures. C replaces about half of the Mo content with Cr to improve on the shortcomings of B, and is important as a heat-resistant alloy that can withstand oxidizing and reducing atmospheres up to 1090°C, and is resistant to high stress and thermal shock, as well as a corrosion-resistant alloy that is resistant to iron chloride (III), wet chlorine gas, and hypochlorite. D is a sulfuric acid resistant alloy containing 9% by mass Si and 3% by mass Cu, F contains 22% by mass Cr, 6.5% by mass Mo, and 16% by mass Fe and is resistant to pitting and stress corrosion cracking, and X contains 22% by mass Cr, 9% by mass Mo, and 18.5% by mass Fe and has excellent oxidation resistance and high temperature strength and is used, for example, for the liner of the combustion chamber of a jet engine.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

Ni-Mo系を主成分とする一群のニッケル合金の商品名．すぐれた耐塩酸合金として，また耐熱合金としても重要である．合金成分によりB，C，D，F，Xなどの種類がある．BはMo 28質量％，Fe 5質量％ を含み，沸点までの全濃度の塩酸のほか，塩化水素ガス，硫酸などに強いが硝酸には侵される．耐熱性もすぐれ，酸化性雰囲気ではMoが酸化蒸発するため，760 ℃ 以下に限定されるが，還元性雰囲気ではさらに高温まで使用できる．CはBの欠点を改良するためMo量の約半分をCrで置換したもので，1090 ℃ までの酸化性，還元性雰囲気に耐え，高応力や熱衝撃にも強い耐熱合金として，また塩化鉄(Ⅲ)や湿った塩素ガス，次亜塩素酸塩にも強い耐食合金としても重要である．DはSi 9質量％，Cu 3質量％ を含む耐硫酸合金，FはCr 22質量％，Mo 6.5質量％，Fe 16質量％ を含み点食，応力腐食割れに強い．XはCr 22質量％，Mo 9質量％，Fe 18.5質量％ を含み，耐酸化性と高温強さにすぐれ，たとえば，ジェットエンジン燃焼室内筒に使われる．

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