| 密度(克/厘米3) density(g/cm3) | 莫氏硬度 Moh'shardnss | 比热 仟卡/公斤.度 specific heat (Kcal/kg℃) | 导热系数 大卡/米.小时.度 thermal conductvity (Kcal/m.h℃) | 线膨胀系数 (m/℃) coefficient of linear expansion(m/℃) | | 3.2 | 9.5 | 0.17 | 20 | 5×10-6 | 致使元件中Sic2含量逐渐增多，电阻随之缓慢增加，为之老化。如水蒸气过多，会促进Sic氧化，由②式反应产生的H2与空气中的O2给合成H2O再反应产生恶性循环。降低元件寿命。 氢气(H2)能使元件机械强度降低。氮气(N2)在1200℃以下能防止Sic氧化1350℃以上与SC发生反应，使Sic分解氯气(Cl2)能使Sic完全分解。 It has good chemical stability and corrosion resistance.At high temmperature,alkalin e material has an etxhing effect on it.If rhe elements are used attemperature above 1000 C for a long time it will react with oxide and wapour as following; ①Sic+2O2→Sio2+CO2 ②Sic+4H2O＝Sio2+4H2+CO2 It will lead to increase of Sio2 contents.Electrical restance will also raise slowly and become ageing.If the vapour is too much,the oxidation of sic will bepromotrd.H2produced by②reactionbonds with O2in the air to form H2Owhic react with sic again,thus causing wicious circle which reduces the life of elements. Hydrogen(H2)can reduce the mechanical strength of elements,while netrogen(N2) can prevent sic from oxidizing at temperature under 1200 C,above11350 C,nitrogen reacts with sic and decompose it.Chlorine(Cl2)can decompose sic completely.
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