表面熔(rong)(rong)覆(fu)技術(shu)可以以較低(di)的(de)成(cheng)本改善(shan)材(cai)(cai)料(liao)的(de)表面性(xing)能(neng)，延長材(cai)(cai)料(liao)的(de)使用壽命(ming)。與其它熔(rong)(rong)覆(fu)技術(shu)相(xiang)比，氬(ya)弧熔(rong)(rong)覆(fu)技術(shu)具有投資和運行費用低(di)、操作方便等優點，而且在氬(ya)氣(qi)的(de)保護下熔(rong)(rong)池中合金元素的(de)燒(shao)損(sun)(sun)和氧化損(sun)(sun)失(shi)也較少，但其熔(rong)(rong)覆(fu)效率低(di)，熔(rong)(rong)覆(fu)層產生裂紋或(huo)剝離的(de)傾向較大(da)，這大(da)大(da)限制(zhi)了(le)該(gai)技術(shu)的(de)發展。科研人員提出(chu)以固(gu)體廢(fei)棄(qi)物粉煤灰為活(huo)(huo)性(xing)劑(ji)，采用活(huo)(huo)性(xing)氬(ya)弧熔(rong)(rong)覆(fu)技術(shu)在Q235鋼表面制(zhi)備了(le)B4C增強(qiang)鐵基活(huo)(huo)性(xing)氬(ya)弧熔(rong)(rong)覆(fu)層，取得了(le)良好效果。

　　粉煤灰(hui)是從煤燃(ran)燒后(hou)的(de)(de)煙氣中收捕的(de)(de)細灰(hui)，粉煤灰(hui)的(de)(de)化(hua)學成(cheng)(cheng)(cheng)分主要(yao)為(wei)SiO2、Al2O3和堿性金屬氧(yang)化(hua)物，可(ke)作(zuo)為(wei)焊(han)接活性劑(ji)使用(yong)。活性氬(ya)弧熔(rong)(rong)(rong)覆(fu)(fu)技(ji)術在等熱(re)量輸入條件下可(ke)使焊(han)縫熔(rong)(rong)(rong)深大幅增加，使熔(rong)(rong)(rong)覆(fu)(fu)層(ceng)與母材(cai)金屬更(geng)好地結合(he)在一起。該技(ji)術在提高熔(rong)(rong)(rong)覆(fu)(fu)效率，降低生產成(cheng)(cheng)(cheng)本的(de)(de)同時，也可(ke)改善熔(rong)(rong)(rong)覆(fu)(fu)層(ceng)的(de)(de)性能。 他們所用(yong)的(de)(de)熔(rong)(rong)(rong)覆(fu)(fu)層(ceng)材(cai)料為(wei)6%B4C、5%硼砂和還(huan)原鐵(tie)粉組成(cheng)(cheng)(cheng)的(de)(de)混合(he)粉，在60MPa壓力下壓制成(cheng)(cheng)(cheng)預置熔(rong)(rong)(rong)覆(fu)(fu)塊，將熔(rong)(rong)(rong)覆(fu)(fu)塊置于Q235鋼表面(mian)進(jin)(jin)行(xing)單道(dao)氬(ya)弧熔(rong)(rong)(rong)覆(fu)(fu)。熔(rong)(rong)(rong)覆(fu)(fu)工藝參數為(wei)：熔(rong)(rong)(rong)覆(fu)(fu)電(dian)流145A，熔(rong)(rong)(rong)覆(fu)(fu)速度120mm/min，氬(ya)氣流量7L/min，弧長4mm，鎢(wu)極(ji)直(zhi)徑(jing)2mm。作(zuo)為(wei)活性劑(ji)的(de)(de)粉煤灰(hui)，其成(cheng)(cheng)(cheng)分為(wei)：SiO2：59.82%，Al2O3：17.32%，Fe2O3：8.23%，CaO：3.64%，K2O：2.75%，MnO：2.61%，Na2O：1.37%，TiO2：0.79%，P2O5：0.26%，MnO：0.11%其它(ta)3.1%。試驗前在800°C下保溫2小(xiao)時進(jin)(jin)行(xing)熱(re)活化(hua)；將其均勻地涂覆(fu)(fu)在預置熔(rong)(rong)(rong)覆(fu)(fu)塊表面(mian)，烘干，然后(hou)進(jin)(jin)行(xing)活性氬(ya)弧熔(rong)(rong)(rong)覆(fu)(fu)。

　　對(dui)所獲活性氬弧(hu)(hu)熔(rong)覆(fu)(fu)層(ceng)的(de)(de)相(xiang)分析表(biao)明，其(qi)中(zhong)不僅存(cun)在(zai)Fe3C，Fe2B，Fe3B，還(huan)存(cun)在(zai)Fe3.5B和(he)Fe23(C,B)等(deng)新相(xiang)，但卻沒有(you)(you)B4C。這(zhe)(zhe)說明涂覆(fu)(fu)粉煤灰活性劑后，提高了(le)焊接熱輸入，使B4C全部分解，從而使得有(you)(you)更(geng)多的(de)(de)硼與鐵發生(sheng)反應，并(bing)且(qie)部分碳(tan)(tan)(tan)元素溶于母材(cai)中(zhong)形成(cheng)了(le)含碳(tan)(tan)(tan)的(de)(de)固(gu)溶體(ti)和(he)碳(tan)(tan)(tan)化物(wu)，這(zhe)(zhe)些新生(sheng)成(cheng)的(de)(de)硼化物(wu)，碳(tan)(tan)(tan)化物(wu)及固(gu)溶體(ti)對(dui)提高熔(rong)覆(fu)(fu)層(ceng)的(de)(de)硬度及耐磨性具有(you)(you)一(yi)定作用。顯微組(zu)織(zhi)檢(jian)測(ce)表(biao)明，活性氬弧(hu)(hu)熔(rong)覆(fu)(fu)層(ceng)的(de)(de)晶粒較(jiao)普通氬弧(hu)(hu)熔(rong)覆(fu)(fu)層(ceng)的(de)(de)更(geng)細(xi)小(xiao)致密，排(pai)布得較(jiao)為規(gui)則，這(zhe)(zhe)說明涂覆(fu)(fu)粉煤灰會促進(jin)一(yi)些細(xi)小(xiao)第二相(xiang)的(de)(de)生(sheng)成(cheng)，并(bing)增加(jia)了(le)形核質點(dian)的(de)(de)數量。

　　顯(xian)(xian)微硬度(du)測試(shi)表明，普(pu)通(tong)氬(ya)(ya)弧(hu)(hu)熔(rong)(rong)(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)顯(xian)(xian)微硬度(du)約為(wei)300HV，活(huo)(huo)性(xing)(xing)氬(ya)(ya)弧(hu)(hu)熔(rong)(rong)(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)顯(xian)(xian)微硬度(du)約為(wei)360HV，而母材的(de)(de)(de)(de)顯(xian)(xian)微硬度(du)約為(wei)130HV。磨(mo)(mo)損(sun)試(shi)驗(yan)表明，母材的(de)(de)(de)(de)磨(mo)(mo)損(sun)量最大，普(pu)通(tong)氬(ya)(ya)弧(hu)(hu)熔(rong)(rong)(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)次之，活(huo)(huo)性(xing)(xing)氬(ya)(ya)弧(hu)(hu)熔(rong)(rong)(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)最小。普(pu)通(tong)氬(ya)(ya)弧(hu)(hu)熔(rong)(rong)(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)耐(nai)磨(mo)(mo)性(xing)(xing)為(wei)母材的(de)(de)(de)(de)1.98倍(bei)，活(huo)(huo)性(xing)(xing)氬(ya)(ya)弧(hu)(hu)熔(rong)(rong)(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)則提高至2.3倍(bei)；活(huo)(huo)性(xing)(xing)氬(ya)(ya)弧(hu)(hu)熔(rong)(rong)(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)耐(nai)磨(mo)(mo)性(xing)(xing)為(wei)普(pu)通(tong)氬(ya)(ya)弧(hu)(hu)熔(rong)(rong)(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)1.16倍(bei)。另外，活(huo)(huo)性(xing)(xing)氬(ya)(ya)弧(hu)(hu)熔(rong)(rong)(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)(fu)(fu)層(ceng)(ceng)和普(pu)通(tong)氬(ya)(ya)弧(hu)(hu)熔(rong)(rong)(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)相對耐(nai)沖蝕(shi)性(xing)(xing)能分別為(wei)母材的(de)(de)(de)(de)4.70倍(bei)和2.52倍(bei)；活(huo)(huo)性(xing)(xing)氬(ya)(ya)弧(hu)(hu)熔(rong)(rong)(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)耐(nai)沖蝕(shi)性(xing)(xing)能為(wei)普(pu)通(tong)氬(ya)(ya)弧(hu)(hu)熔(rong)(rong)(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)1.86倍(bei)。

　　上(shang)述試(shi)驗(yan)證(zheng)明，以粉煤灰為活性(xing)劑，采(cai)用活性(xing)氬(ya)弧熔覆技(ji)術在鋼材(cai)表(biao)面制備活性(xing)氬(ya)弧熔覆層可以明顯(xian)提高鋼材(cai)的(de)耐磨粒磨損性(xing)能(neng)和耐沖蝕磨損性(xing)能(neng)。