多(duo)(duo)(duo)(duo)(duo)(duo)孔(kong)(kong)(kong)(kong)(kong)陶(tao)(tao)(tao)瓷(ci)(ci)(ci)是(shi)一種三維網(wang)狀結構(gou)的(de)陶(tao)(tao)(tao)瓷(ci)(ci)(ci)材料。多(duo)(duo)(duo)(duo)(duo)(duo)孔(kong)(kong)(kong)(kong)(kong)陶(tao)(tao)(tao)瓷(ci)(ci)(ci)結合了陶(tao)(tao)(tao)瓷(ci)(ci)(ci)材料和泡沫結構(gou)的(de)特性(xing)(xing)，既具(ju)(ju)有(you)(you)低(di)密(mi)度、輕(qing)質量(liang)、高(gao)(gao)(gao)孔(kong)(kong)(kong)(kong)(kong)隙(xi)率(lv)和導熱系數(shu)小(xiao)的(de)特點，又具(ju)(ju)有(you)(you)耐(nai)高(gao)(gao)(gao)溫(wen)、耐(nai)腐(fu)(fu)蝕、機械(xie)性(xing)(xing)能高(gao)(gao)(gao)的(de)特點。多(duo)(duo)(duo)(duo)(duo)(duo)孔(kong)(kong)(kong)(kong)(kong)陶(tao)(tao)(tao)瓷(ci)(ci)(ci)與致密(mi)陶(tao)(tao)(tao)瓷(ci)(ci)(ci)相比(bi)，具(ju)(ju)有(you)(you)低(di)密(mi)度、輕(qing)質量(liang)、高(gao)(gao)(gao)孔(kong)(kong)(kong)(kong)(kong)隙(xi)率(lv)的(de)特點，因(yin)此(ci)，多(duo)(duo)(duo)(duo)(duo)(duo)孔(kong)(kong)(kong)(kong)(kong)陶(tao)(tao)(tao)瓷(ci)(ci)(ci)在流(liu)體(ti)(ti)過濾、吸附、提純等(deng)領域有(you)(you)廣泛的(de)應(ying)(ying)用(yong)(yong);與有(you)(you)機泡沫材料相比(bi)，多(duo)(duo)(duo)(duo)(duo)(duo)孔(kong)(kong)(kong)(kong)(kong)陶(tao)(tao)(tao)瓷(ci)(ci)(ci)有(you)(you)耐(nai)高(gao)(gao)(gao)溫(wen)、耐(nai)腐(fu)(fu)蝕、較好的(de)阻燃性(xing)(xing)和導熱系數(shu)較低(di)的(de)特點，因(yin)此(ci)多(duo)(duo)(duo)(duo)(duo)(duo)孔(kong)(kong)(kong)(kong)(kong)陶(tao)(tao)(tao)瓷(ci)(ci)(ci)將逐漸(jian)取代有(you)(you)機泡沫類材料，在吸音、隔熱和保(bao)溫(wen)等(deng)工程應(ying)(ying)用(yong)(yong)方面被大量(liang)采用(yong)(yong)。多(duo)(duo)(duo)(duo)(duo)(duo)孔(kong)(kong)(kong)(kong)(kong)陶(tao)(tao)(tao)瓷(ci)(ci)(ci)還可用(yong)(yong)作催化劑載體(ti)(ti)。由于多(duo)(duo)(duo)(duo)(duo)(duo)孔(kong)(kong)(kong)(kong)(kong)陶(tao)(tao)(tao)瓷(ci)(ci)(ci)具(ju)(ju)有(you)(you)高(gao)(gao)(gao)比(bi)表(biao)面積、高(gao)(gao)(gao)孔(kong)(kong)(kong)(kong)(kong)隙(xi)率(lv)、耐(nai)高(gao)(gao)(gao)溫(wen)、耐(nai)酸堿侵(qin)蝕、遇有(you)(you)機溶劑不發(fa)生(sheng)反(fan)應(ying)(ying)、不溶解、機械(xie)性(xing)(xing)能和硬(ying)度較高(gao)(gao)(gao)等(deng)眾多(duo)(duo)(duo)(duo)(duo)(duo)優(you)點，因(yin)此(ci)利用(yong)(yong)多(duo)(duo)(duo)(duo)(duo)(duo)孔(kong)(kong)(kong)(kong)(kong)陶(tao)(tao)(tao)瓷(ci)(ci)(ci)作為催化載體(ti)(ti)可以保(bao)證催化反(fan)應(ying)(ying)迅速、徹底，如汽車尾氣的(de)無害化處理、有(you)(you)毒或污染性(xing)(xing)氣體(ti)(ti)和液(ye)體(ti)(ti)排放前(qian)的(de)催化凈化等(deng)。此(ci)外，多(duo)(duo)(duo)(duo)(duo)(duo)孔(kong)(kong)(kong)(kong)(kong)陶(tao)(tao)(tao)瓷(ci)(ci)(ci)在生(sheng)物材料方面的(de)應(ying)(ying)用(yong)(yong)也有(you)(you)著較好的(de)前(qian)景。

目前(qian)多(duo)孔陶(tao)(tao)瓷的(de)(de)造孔方(fang)法(fa)(fa)有(you)(you)很多(duo)，包括添(tian)加造孔劑法(fa)(fa)、直(zhi)接(jie)發(fa)泡(pao)(pao)(pao)法(fa)(fa)、有(you)(you)機泡(pao)(pao)(pao)沫(mo)(mo)浸漬法(fa)(fa)、冷凍凝膠法(fa)(fa)、冷凍干(gan)(gan)燥法(fa)(fa)、溶膠-凝膠法(fa)(fa)等。其中(zhong)(zhong)直(zhi)接(jie)發(fa)泡(pao)(pao)(pao)法(fa)(fa)就是指(zhi)將(jiang)表(biao)面(mian)(mian)(mian)(mian)活(huo)性(xing)(xing)(xing)劑加入(ru)陶(tao)(tao)瓷漿(jiang)料(liao)中(zhong)(zhong)，通(tong)(tong)過(guo)(guo)機械攪拌向陶(tao)(tao)瓷漿(jiang)料(liao)中(zhong)(zhong)引入(ru)氣泡(pao)(pao)(pao)，降(jiang)(jiang)低漿(jiang)體的(de)(de)表(biao)面(mian)(mian)(mian)(mian)張(zhang)(zhang)力，形(xing)成在(zai)一定(ding)(ding)時間內(nei)具有(you)(you)穩定(ding)(ding)性(xing)(xing)(xing)的(de)(de)泡(pao)(pao)(pao)沫(mo)(mo)陶(tao)(tao)瓷漿(jiang)料(liao)，在(zai)泡(pao)(pao)(pao)沫(mo)(mo)消散之(zhi)前(qian)，通(tong)(tong)過(guo)(guo)固化成型、干(gan)(gan)燥制(zhi)得(de)多(duo)孔陶(tao)(tao)瓷坯體，然后(hou)將(jiang)坯體進行燒結，就可以制(zhi)得(de)多(duo)孔陶(tao)(tao)瓷。表(biao)面(mian)(mian)(mian)(mian)活(huo)性(xing)(xing)(xing)劑是一種(zhong)可以吸(xi)附在(zai)液(ye)(ye)體表(biao)面(mian)(mian)(mian)(mian)、或(huo)者(zhe)堆積在(zai)兩相(xiang)之(zhi)間的(de)(de)界(jie)面(mian)(mian)(mian)(mian)上，通(tong)(tong)過(guo)(guo)改變界(jie)面(mian)(mian)(mian)(mian)的(de)(de)表(biao)面(mian)(mian)(mian)(mian)張(zhang)(zhang)力，使液(ye)(ye)體或(huo)漿(jiang)體更容易起(qi)泡(pao)(pao)(pao)的(de)(de)物質，因(yin)為表(biao)面(mian)(mian)(mian)(mian)活(huo)性(xing)(xing)(xing)劑溶于液(ye)(ye)體后(hou)能夠降(jiang)(jiang)低液(ye)(ye)體的(de)(de)表(biao)面(mian)(mian)(mian)(mian)張(zhang)(zhang)力，有(you)(you)較好的(de)(de)起(qi)泡(pao)(pao)(pao)性(xing)(xing)(xing)能，因(yin)此也(ye)稱為發(fa)泡(pao)(pao)(pao)劑。當(dang)氣泡(pao)(pao)(pao)產(chan)生(sheng)后(hou)，溶液(ye)(ye)中(zhong)(zhong)的(de)(de)表(biao)面(mian)(mian)(mian)(mian)活(huo)性(xing)(xing)(xing)劑分子(zi)能夠快速(su)地吸(xi)附在(zai)氣液(ye)(ye)界(jie)面(mian)(mian)(mian)(mian)上，定(ding)(ding)向排列，降(jiang)(jiang)低表(biao)面(mian)(mian)(mian)(mian)張(zhang)(zhang)力，同(tong)時表(biao)面(mian)(mian)(mian)(mian)活(huo)性(xing)(xing)(xing)劑的(de)(de)疏水基團(tuan)在(zai)范德華力和疏水作用下(xia)相(xiang)互吸(xi)引，使表(biao)面(mian)(mian)(mian)(mian)活(huo)性(xing)(xing)(xing)劑分子(zi)吸(xi)附在(zai)氣液(ye)(ye)界(jie)面(mian)(mian)(mian)(mian)之(zhi)間，形(xing)成緊密堆積的(de)(de)分子(zi)層(ceng)，有(you)(you)利于提(ti)高界(jie)面(mian)(mian)(mian)(mian)的(de)(de)穩定(ding)(ding)性(xing)(xing)(xing)，因(yin)此表(biao)面(mian)(mian)(mian)(mian)活(huo)性(xing)(xing)(xing)劑分子(zi)的(de)(de)加入(ru)可以起(qi)到穩定(ding)(ding)泡(pao)(pao)(pao)沫(mo)(mo)的(de)(de)作用。

發泡(pao)劑摻(chan)量對(dui)多孔陶(tao)瓷(ci)材(cai)料性能的影響

圖(tu)1為固含量(liang)(liang)(liang)60%、SDS摻(chan)量(liang)(liang)(liang)分別為0.02%、0.04%、0.06%、0.08%、0.1%下所制備的(de)(de)多孔(kong)(kong)(kong)(kong)陶(tao)(tao)(tao)(tao)瓷(ci)(ci)(ci)坯體(ti)，經過(guo)1190℃、保溫2 h燒結后(hou)(hou)的(de)(de)樣(yang)品性能(neng)。從(cong)圖(tu)中可(ke)以(yi)看出，多孔(kong)(kong)(kong)(kong)陶(tao)(tao)(tao)(tao)瓷(ci)(ci)(ci)樣(yang)品的(de)(de)體(ti)積(ji)密度(du)和抗壓(ya)強(qiang)度(du)隨發(fa)(fa)泡(pao)劑摻(chan)量(liang)(liang)(liang)的(de)(de)增加(jia)而減(jian)小。當SDS的(de)(de)摻(chan)入(ru)量(liang)(liang)(liang)由(you)0.02%提高至0.1%時(shi)，樣(yang)品的(de)(de)密度(du)由(you)890.53降(jiang)(jiang)(jiang)至361.0 kg/m3，抗壓(ya)強(qiang)度(du)由(you)1.7下降(jiang)(jiang)(jiang)至0.2 MPa。當SDS溶(rong)于水并經過(guo)高速攪拌后(hou)(hou)，SDS分子可(ke)以(yi)吸附(fu)到(dao)(dao)氣(qi)(qi)液(ye)(ye)界面上降(jiang)(jiang)(jiang)低表面張(zhang)力并產生大量(liang)(liang)(liang)的(de)(de)氣(qi)(qi)泡(pao)，這些(xie)氣(qi)(qi)泡(pao)會緊(jin)密堆(dui)積(ji)在一起，氣(qi)(qi)泡(pao)之間有液(ye)(ye)膜(mo)將其隔開，將氣(qi)(qi)泡(pao)引入(ru)到(dao)(dao)陶(tao)(tao)(tao)(tao)瓷(ci)(ci)(ci)漿(jiang)料中后(hou)(hou)，陶(tao)(tao)(tao)(tao)瓷(ci)(ci)(ci)原料分散(san)在氣(qi)(qi)泡(pao)液(ye)(ye)膜(mo)間，形成(cheng)骨(gu)架(jia)支撐，干燥(zao)后(hou)(hou)陶(tao)(tao)(tao)(tao)瓷(ci)(ci)(ci)原料液(ye)(ye)相消失，固化形成(cheng)含孔(kong)(kong)(kong)(kong)隙(xi)的(de)(de)多孔(kong)(kong)(kong)(kong)陶(tao)(tao)(tao)(tao)瓷(ci)(ci)(ci)坯體(ti)，引入(ru)的(de)(de)氣(qi)(qi)泡(pao)越(yue)多，多孔(kong)(kong)(kong)(kong)陶(tao)(tao)(tao)(tao)瓷(ci)(ci)(ci)的(de)(de)孔(kong)(kong)(kong)(kong)隙(xi)率越(yue)高，孔(kong)(kong)(kong)(kong)壁(bi)越(yue)薄，陶(tao)(tao)(tao)(tao)瓷(ci)(ci)(ci)骨(gu)架(jia)越(yue)細;當氣(qi)(qi)泡(pao)的(de)(de)引入(ru)量(liang)(liang)(liang)過(guo)多時(shi)，骨(gu)架(jia)易(yi)發(fa)(fa)生斷裂，此時(shi)多孔(kong)(kong)(kong)(kong)陶(tao)(tao)(tao)(tao)瓷(ci)(ci)(ci)的(de)(de)抗壓(ya)強(qiang)度(du)就會降(jiang)(jiang)(jiang)低。

圖1不同(tong)發泡劑(ji)摻量下(xia)多(duo)孔(kong)陶瓷樣品的性能(neng)(a)體積密度和(he)抗(kang)壓強度;(b)孔(kong)隙率

圖2不同SDS摻(chan)量(a:0.04%;b:0.08%;c:0.1%)的多(duo)孔陶瓷樣品的SEM照片(pian)

圖2是(shi)SDS摻(chan)量(liang)分(fen)(fen)別為(wei)0.04%、0.08%、0.1%的(de)(de)(de)多(duo)(duo)孔(kong)(kong)陶瓷樣品(pin)的(de)(de)(de)SEM照片。從(cong)圖可(ke)見(jian)，當SDS摻(chan)量(liang)為(wei)0.04%和0.08%時，氣(qi)(qi)(qi)孔(kong)(kong)尺寸(cun)在100～200μm左(zuo)右;當SDS摻(chan)量(liang)為(wei)0.1%時，多(duo)(duo)孔(kong)(kong)陶瓷中既有100～200μm之(zhi)間(jian)的(de)(de)(de)孔(kong)(kong)，又有200～600μm之(zhi)間(jian)的(de)(de)(de)孔(kong)(kong)，氣(qi)(qi)(qi)孔(kong)(kong)尺寸(cun)分(fen)(fen)布較(jiao)為(wei)寬泛。這是(shi)因(yin)為(wei)添加表面活性劑所(suo)(suo)產(chan)(chan)生(sheng)(sheng)(sheng)的(de)(de)(de)泡(pao)(pao)(pao)(pao)(pao)沫狀態是(shi)熱力學非穩態孔(kong)(kong)，同時，在一定(ding)的(de)(de)(de)范(fan)圍內(nei)，表面活性劑的(de)(de)(de)添加量(liang)越多(duo)(duo)，所(suo)(suo)產(chan)(chan)生(sheng)(sheng)(sheng)的(de)(de)(de)泡(pao)(pao)(pao)(pao)(pao)沫就相對越多(duo)(duo)。當產(chan)(chan)生(sheng)(sheng)(sheng)的(de)(de)(de)氣(qi)(qi)(qi)泡(pao)(pao)(pao)(pao)(pao)過多(duo)(duo)時，表面活性劑在氣(qi)(qi)(qi)液(ye)界面的(de)(de)(de)吸附能量(liang)相對較(jiao)小(xiao)，會(hui)導(dao)致(zhi)(zhi)吸附分(fen)(fen)子容易(yi)從(cong)界面脫附，進而影響(xiang)了泡(pao)(pao)(pao)(pao)(pao)沫的(de)(de)(de)穩定(ding)性，此時泡(pao)(pao)(pao)(pao)(pao)沫就會(hui)發生(sheng)(sheng)(sheng)合(he)并、粗化，甚至破裂的(de)(de)(de)現象。當SDS的(de)(de)(de)加入(ru)量(liang)較(jiao)少時，高(gao)(gao)速攪(jiao)拌形(xing)成的(de)(de)(de)氣(qi)(qi)(qi)泡(pao)(pao)(pao)(pao)(pao)量(liang)較(jiao)少，陶瓷原(yuan)料分(fen)(fen)散(san)在泡(pao)(pao)(pao)(pao)(pao)沫之(zhi)間(jian)，形(xing)成骨架支(zhi)撐，阻礙了泡(pao)(pao)(pao)(pao)(pao)沫的(de)(de)(de)合(he)并與粗化。當SDS的(de)(de)(de)摻(chan)入(ru)量(liang)增(zeng)大(da)，高(gao)(gao)速攪(jiao)拌所(suo)(suo)產(chan)(chan)生(sheng)(sheng)(sheng)的(de)(de)(de)泡(pao)(pao)(pao)(pao)(pao)沫增(zeng)多(duo)(duo)，氣(qi)(qi)(qi)泡(pao)(pao)(pao)(pao)(pao)與氣(qi)(qi)(qi)泡(pao)(pao)(pao)(pao)(pao)之(zhi)間(jian)緊密堆積，從(cong)能量(liang)角度(du)來講，此時氣(qi)(qi)(qi)泡(pao)(pao)(pao)(pao)(pao)間(jian)更趨向于向低勢能方向發展，因(yin)此產(chan)(chan)生(sheng)(sheng)(sheng)泡(pao)(pao)(pao)(pao)(pao)沫合(he)并，泡(pao)(pao)(pao)(pao)(pao)沫的(de)(de)(de)尺寸(cun)增(zeng)大(da)，進而導(dao)致(zhi)(zhi)多(duo)(duo)孔(kong)(kong)陶瓷孔(kong)(kong)隙尺寸(cun)的(de)(de)(de)變(bian)化。