物理性能
Physical
元件質地硬而脆,耐急冷急熱,高溫下不易變形,其它物理性能如下表:
The elements are brittle with high cold-resistance and heat-resistance.It's uneasy to be out kf shape.Its other physical properties are as follows:
化學性質
Chemical property
硅碳棒有良好的化學穩定性,抗酸能力強。在高溫條件下堿性物質對其有侵蝕作用。
元件在1000℃以上長期使用能與氧氣和水蒸氣發生如下作用:
①Sic+2O2→Sio2+CO2
②Sic+4H2O=Sio2+4H2+CO2
密度(克/厘米3)
density(g/cm3) 莫氏硬度
Moh'shardnss 比熱
仟卡/公斤.度
specific heat
(Kcal/kg℃) 導熱系數
大卡/米.小時.度
thermal conductvity
(Kcal/m.h℃) 線膨脹系數
(m/℃)
coefficient of linear expansion(m/℃)
3.2 9.5 0.17 20 5×10-6
致使元件中Sic2含量逐漸增多,電阻隨之緩慢增加,為之老化。如水蒸氣過多,會促進Sic氧化,由②式反應產生的H2與空氣中的O2給合成H2O再反應產生惡性循環。降低元件壽命。
氫氣(H2)能使元件機械強度降低。氮氣(N2)在1200℃以下能防止Sic氧化1350℃以上與SC發生反應,使Sic分解氯氣(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.