Potassium titanate whiskers material

More than 100 different materials have to date been produced as whiskers and characterized. However, only SiC- (50 to 100 t, 1996) and potassium titanate whiskers (ca. 5000 t) have achieved commercial importance. Important properties of whiskers are summarized in Table 5.2-18. 

Potassium titanate whiskers were found to improve the tribological properties of NAO friction materials. These soft, synthetic refractory materials stabilize friction level, reduce pad wear, noise, fade, thermal conductivity, control porosity, and provide thermal reinforcement. Fibrous potassium titanates are being replaced by platelet and powder versions because of health concerns associated with respirable fibers. 

Potassium titanate whiskers can be used as thermal insulation material, electrical insulating material, catalyst carriers, filtration material, friction material, and so on based on their special performances. In addition, they are applied as... 

When potassium titanate whiskers modified by a coupling agent are filled into PE material with ultrahigh molecular weight, the hardness of composite material increases significantly, as shown in Table 4.5. 

In recent years, there has been a breakthrough in the manufacturing cost of potassium titanate whiskers, aluminum borate whiskers, and so forth. Meanwhile, inexpensive and high-quality inorganic whiskers such as calcium carbonate, calcium sulfate, and magnesium are successfully synthesized, which makes inorganic whiskers a new type of filling modification material of polymer materials. This field has become a research hotspot all over the world and reveals broad application and market prospects. 

PP is the most studied material in whisker reinforcing and toughening modification research. Zhou et al. studied PP modified with potassium titanate whiskers and found that the notched impact strength increased by 20% over that of pure PP. Lu et al. studied PE composite material modified with magnesium sulfate whiskers, and found that when... 

The most studied anti-wear material modified by whiskers is PEEK. Wang et al." compared the performances of PEEK before and after modification with potassium titanate whiskers. The friction and wear performances of the latter showed obvious improvement over the former. Under 300 N, the wear resistance of the latter increases 2.64 and 2.11 times than the former, respectively. In addition, calcium carbonate whiskers have an excellent anti-friction effect on PEEK composite material. When the whisker content is less than 15%, the wear rate of the material decreases dramatically. The wear rate of the... 

Shi et al. 5 also discovered that the wear resistance of PTFE improved about 300 times that of the pure PTFE after adding potassium titanate whiskers. Hu and Liang added aluminum borate whiskers and calcium sulfate whiskers respectively to bismaleimide resin and found that the wearability of both materials improved. When the content of aluminum borate whiskers was 8%, the wear rate of the material declined from 4.39 X 10" mmVCN irO to 1.42 x 10 mmV(N-m). When the content of calcium sulfate whiskers was 10%, the wear rate of the material declined from 2.89 x 10" mmy(N-m) to 1.28 x 10" mmVCN-m). Thus it can be seen that the high hardness of inorganic whiskers determines their broad application prospects in the field of polymer wear-resistant materials. 

Xin Feng, Donghui Chen, Xiaohong Jiang. Study on friction and wear properties of potassium titanate whiskers-reinforced PTFE composites. Polymer Materials Science and Engineering, 20(5) 129-132, 2004. 

Wu et al.3 compared the friction and wear properties of phenolic resin-filled calcium carbonate whiskers and potassium titanate whiskers. They found that calcium carbonate whisker-filled friction material shows the lowest sensitivity to speed and easy to cause surface abrasion whereas potassium titanate whiskers-filled friction material shows the lowest sensitivity to load and the highest sensitivity to speed. 

Aluminium titanate (tielite, Al2Ti05) has excellent thermal shock resistance but poor mechanical strength which can, however, be improved by reinforcing with whiskers of a related phase such as potassium hollandite (K2Al2Ti60i6). Such composites can be formed by thermal decomposition of sol-gel precursors, reaction sintering of the two phases or by thermal treatment of an appropriate glass-ceramic material. Al MS NMR has been used to study the co-formation of these two phases during thermal treatment, and indicates that hollandite crystallises as whiskers within the tielite matrix (Kohn and Jansen 1998). 

---