钨(wu)是(shi)熔(rong)(rong)(rong)(rong)(rong)点(dian)(dian)(dian)最(zui)高的难(nan)(nan)熔(rong)(rong)(rong)(rong)(rong)金属(shu)。一(yi)般熔(rong)(rong)(rong)(rong)(rong)点(dian)(dian)(dian)高于1650℃并有(you)一(yi)定储 量的金属(shu)以(yi)及熔(rong)(rong)(rong)(rong)(rong)点(dian)(dian)(dian)高于锆熔(rong)(rong)(rong)(rong)(rong)点(dian)(dian)(dian)（1852℃）的金属(shu)称(cheng)为难(nan)(nan)熔(rong)(rong)(rong)(rong)(rong)金属(shu)。典型的难(nan)(nan)熔(rong)(rong)(rong)(rong)(rong)金属(shu)有(you)钨(wu)、钽、钼(mu)、铌(ni)、铪、铬、钒(fan)、锆和钛。作为一(yi)种难(nan)(nan)熔(rong)(rong)(rong)(rong)(rong)金属(shu)，钨(wu)最(zui)重要的优点(dian)(dian)(dian)是(shi)有(you)良好的高温(wen)强度，对(dui)熔(rong)(rong)(rong)(rong)(rong)融(rong)碱金属(shu)和蒸气有(you)良好的耐蚀性能(neng)，钨(wu)只(zhi)有(you)在(zai)1000℃以(yi)上(shang)才(cai)出(chu)现氧化(hua)物(wu)挥发和液相(xiang)氧化(hua)物(wu)。但(dan)是(shi)，它(ta)同时也具有(you)塑(su)性－脆(cui)性转变温(wen)度较高，在(zai)室(shi)温(wen)下难(nan)(nan)以(yi)塑(su)性加(jia)工的缺点(dian)(dian)(dian)。以(yi)钨(wu)为代表的难(nan)(nan)熔(rong)(rong)(rong)(rong)(rong)金属(shu)在(zai)冶金、化(hua)工、电子(zi)、光源、机械工业等部(bu)门得到了广(guang)泛应用(yong)。
