钨是熔(rong)(rong)(rong)点(dian)(dian)最高(gao)的(de)(de)难熔(rong)(rong)(rong)金(jin)属(shu)。一般熔(rong)(rong)(rong)点(dian)(dian)高(gao)于(yu)1650℃并有(you)(you)(you)一定储 量的(de)(de)金(jin)属(shu)以(yi)及熔(rong)(rong)(rong)点(dian)(dian)高(gao)于(yu)锆(gao)熔(rong)(rong)(rong)点(dian)(dian)（1852℃）的(de)(de)金(jin)属(shu)称(cheng)为(wei)难熔(rong)(rong)(rong)金(jin)属(shu)。典型(xing)的(de)(de)难熔(rong)(rong)(rong)金(jin)属(shu)有(you)(you)(you)钨、钽、钼、铌、铪、铬、钒(fan)、锆(gao)和(he)钛。作为(wei)一种难熔(rong)(rong)(rong)金(jin)属(shu)，钨最重要的(de)(de)优点(dian)(dian)是有(you)(you)(you)良好(hao)的(de)(de)高(gao)温(wen)强度，对熔(rong)(rong)(rong)融碱(jian)金(jin)属(shu)和(he)蒸气(qi)有(you)(you)(you)良好(hao)的(de)(de)耐蚀(shi)性(xing)能，钨只有(you)(you)(you)在1000℃以(yi)上(shang)才(cai)出现氧化(hua)物挥发和(he)液(ye)相氧化(hua)物。但是，它同时也具有(you)(you)(you)塑(su)性(xing)－脆性(xing)转变(bian)温(wen)度较(jiao)高(gao)，在室(shi)温(wen)下难以(yi)塑(su)性(xing)加工的(de)(de)缺点(dian)(dian)。以(yi)钨为(wei)代(dai)表(biao)的(de)(de)难熔(rong)(rong)(rong)金(jin)属(shu)在冶金(jin)、化(hua)工、电子、光源、机(ji)械(xie)工业等部门得到了广(guang)泛应用。
