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PTFE 復(fù)合材料的摩擦系數(shù)比非填充PTFE 的略高,且填充PTFE 復(fù)合材料的摩擦系數(shù)隨填料含量的增加而有所增大. 由于PTFE 復(fù)合材料是粘彈性聚合物, 在外力的作用下發(fā)生粘彈性變形, 其摩擦系數(shù)的變化服從L= K P n- 1 (K 為常數(shù), P 為載荷, 2ö3 < n< 1) [5, 8 ]. 由此可以看出, PTFE 復(fù)合材料的摩擦系數(shù)隨著載荷的增大而減小. 當(dāng)載荷增大到一定值時, 由于摩擦表面溫度升高, 材料的機械強度降低, 承載能力下降, 摩擦系數(shù)又會有所增大. 而A l2O 3 含量較高的填充PTFE 復(fù)合材料在較高載荷作用下, 填料A l2O 3顆?？杀焕蚊撾xPTFE 基體, 從而加劇塑性變形,導(dǎo)致摩擦系數(shù)增大.

3　結(jié)論a. 　納米A l2O 3 填料可提高PTFE 的耐磨性. 但納米A l2O 3 填料加劇復(fù)合材料中PTFE 基體的塑性變形, 且A l2O 3 含量越高相應(yīng)的塑性變形越嚴(yán)重. 在本文試驗條件下, 當(dāng)A l2O 3 的含量為10% 左右時, 填充PTFE 復(fù)合材料的耐磨性最佳.b. 　納米A l2O 3 填充PTFE 復(fù)合材料的摩擦系數(shù)較PTFE 的摩擦系數(shù)大, 且隨填料含量的增加,PTFE 復(fù)合材料的摩擦系數(shù)有所增大.參考文獻:[ 1 ]　Tanaka K, Kawakam i S. Effect of various fillers on the fric-tion and wear of PTFE2based compo sites [ J ]. W ear, 1982,79: 221～ 234[ 2 ]　L u X C, W en S Z, Tong J , et al. W ettability, so il adhesion,abrasion and friction wear of PTFE ( + PPS ) + A l2O3compo sites[J ]. W ear, 1996, 193: 48～ 55[ 3 ]　宮德利, 薛群基, 王弘立. PTFE 復(fù)合材料磨損機理的研究[J ]. 固體潤滑, 1989, 9 (2) : 88～ 94[ 4 ]　李同生, 孫守鎂, 胡廷永, 等. 聚四氟乙烯磨損機理的探討[J ]. 摩擦學(xué)學(xué)報, 1992, 12 (3) : 222～ 232[ 5 ]　張招柱, 薛群基, 劉維民, 等. 幾種金屬氧化物填充聚四氟乙烯復(fù)合材料在干摩擦條件下的摩擦磨損性能[ J ]. 摩擦學(xué)學(xué)報, 1997, 17 (1) : 45～ 52[ 6 ]　楊劍, 滕鳳思. 納米材料綜述[J ]. 材料導(dǎo)報, 1997, 11 (2) : 6～ 10[ 7 ]　陳夕, 黃麗, 徐定宇. 納米材料的進展及其在塑料中的應(yīng)用[J ]. 國外塑料, 1995, 13 (3) : 5～ 12[ 8 ]　王承鶴. 塑料摩擦學(xué)[M ]. 北京: 機械工業(yè)出版社, 1994

Fr iction andWear Properties of Nanocrystall ineAl2O3 Filled-PTFE Compos itesHE Chun2x ia1, SH IL i2p ing1, SHEN Hu i2p ing2(1. A g ricu ltu ral E ng ineering Colleg e, N anj ing A g ricu ltu ral U niv ersity , N anj ing 210032, Ch ina;2. N anj ing F iberg lass R esearch and D esig n Institu te, N anj ing 210012, Ch ina)Abstract: The f rict ion and w ear p ropert ies of po lytet raf luo roethylene ( PTFE ) compo sites f illed w ithnanocrystalline A l2O 3w ere evaluated w ith anMM 2200 f rict ion and w ear tester. The wo rn su rfaces of PTFEcompo sites w ere exam ined by mean s of scann ing elect ron m icro scopy (SEM ). It has been found that theinco rpo rat ion of nanocrystalline A l2O 3 in to PTFE increases the w ear resistance of PTFE bu t wo rsen s thef rict ion2reduct ion perfo rmance to some ex ten t. The f rict ion coeff icien t of PTFE compo sites increasesw ith theincreasing of A l2O 3 con ten t. The best w ear2resistance of the compo site is reached at a mass f ract ion of A l2O 3abou t 10%. Mo reover, nanocrystalline A l2O 3 as the f iller in PTFE leads to enhanced p last ic defo rmat ion ofPTFE mat rix in the compo site, w h ich sub sequen t ly increases the f rict ion coeff icien t.Key words: nanocrystalline A l2O 3; PTFE; f rict ion and w ear behavio rs