Al_(2)O_(3)-ZrO_(2)-TiO_(2)coatings were successfully prepared by plasma spraying Al_(2)O_(3)-ZrO_(2)composite powders with and without TiO_(2)addition.The effects of TiO_(2)on the phase composition,microstructure and...Al_(2)O_(3)-ZrO_(2)-TiO_(2)coatings were successfully prepared by plasma spraying Al_(2)O_(3)-ZrO_(2)composite powders with and without TiO_(2)addition.The effects of TiO_(2)on the phase composition,microstructure and properties of the Al_(2)O_(3)-ZrO_(2)coating were studied.The results show that the Al_(2)O_(3)-ZrO_(2)-TiO_(2)composite powder was composed of t-ZrO_(2),a-Al_(2)O_(3),m-ZrO_(2)and rutile,while the Al_(2)O_(3)-ZrO_(2)-TiO_(2)composite coating consisted of t-ZrO_(2),a-Al_(2)O_(3)and c-Al_(2)O_(3).The diffraction peaks of TiO_(2)could not be detected in the Al_(2)O_(3)-ZrO_(2)-TiO_(2)coating even up to10 wt%TiO_(2)addition.The reason may be that TiO_(2)was dissolved in the amorphous phase or formed solid solution with c-Al_(2)O_(3)phase in the coating during cooling.Compared with the Al_(2)O_(3)-ZrO_(2)coating,the as-prepared Al_(2)O_(3)-ZrO_(2)-TiO_(2)coating had denser microstructure,less microcracks and more amorphous phases.The density of the Al_(2)O_(3)-ZrO_(2)-TiO_(2)coating increased with the increase of TiO_(2)content.The Al_(2)O_(3)-ZrO_(2)-10 wt%TiO_(2)coating had the most uniform and dense microstructure,possessed higher toughness,adhesive strength and wear resistance compared with the Al_(2)O_(3)-ZrO_(2)coating,which was due to its lower porosity and more uniform microstructure.展开更多
The Cr_(7)C_(3)−CrSi_(2)−Al_(2)O_(3)composite coatings were prepared by plasma spraying Cr_(7)C_(3)−CrSi_(2)−Al_(2)O_(3)and Al−Cr2O3−SiC composite powders,respectively.The microstructure,formation mechanism and proper...The Cr_(7)C_(3)−CrSi_(2)−Al_(2)O_(3)composite coatings were prepared by plasma spraying Cr_(7)C_(3)−CrSi_(2)−Al_(2)O_(3)and Al−Cr2O3−SiC composite powders,respectively.The microstructure,formation mechanism and properties of the two Cr_(7)C_(3)−CrSi_(2)−Al_(2)O_(3)composite coatings obtained by plasma spraying were investigated,and the reaction mechanism of the Al−Cr_(2)O_(3)−SiC system was explored.The results show that the coating obtained by plasma spraying Al−Cr_(2)O_(3)−SiC composite powders had thinner lamella and more tortuous interlayer interface,and the in-situ synthesized Cr_(7)C_(3),CrSi_(2)and Al_(2)O_(3)in the coating were all nano-crystallines.Compared with the Cr_(7)C_(3)−CrSi_(2)−Al_(2)O_(3)coating prepared by plasma spraying Cr_(7)C_(3)−CrSi_(2)−Al_(2)O_(3)composite powders,the plasma-sprayed Cr_(7)C_(3)−CrSi_(2)−Al_(2)O_(3)coating obtained from Al−Cr_(2)O_(3)−SiC composite powders had higher density,higher microhardness(increased by 20%),better fracture toughness and lower wear rate(reduced by 28%).展开更多
High porosity and high brittleness are the main reasons that limit the long-term service life of the alumina-titanium oxide composite coating.Herein,a metastable nanostructured aluminatitanium oxide composite coating ...High porosity and high brittleness are the main reasons that limit the long-term service life of the alumina-titanium oxide composite coating.Herein,a metastable nanostructured aluminatitanium oxide composite coating with high density and high properties was synthesized by plasma spraying of TiO_(2)-Al composite powder.The main phases of the metastable nanostructured alumina-titanium oxide wereγ-Al_(2)O_(3),TiO and AlTiO_(2).The coating,as prepared,contains various metastable microstructures,such as fine-grained,intra-/inter-granular,and"self-locking"microstructures.These metastable microstruc-tures are important for the improvement of hardness and toughness of the coating.Compared with other alumina-based composite coatings,the metastable nanostructured aluminatitanium oxide composite coating showed the most impressive overall performance.The reinforcing and toughening mechanism of the metastable alumina-titanium oxide composite coating included fine grain strengthening and self-toughening of the metastable microstructure.展开更多
基金the National Natural Science Foundation of China(Nos.51672067,51541208 and 51102074)the Natural Science Foundation of Hebei Province(Nos.E2018202034 and E2015202070)+1 种基金the Talent Training Project in Hebei Province(No.A2016002026)the Top Talents in Universities in Hebei Province(No.SLRC2017027)。
文摘Al_(2)O_(3)-ZrO_(2)-TiO_(2)coatings were successfully prepared by plasma spraying Al_(2)O_(3)-ZrO_(2)composite powders with and without TiO_(2)addition.The effects of TiO_(2)on the phase composition,microstructure and properties of the Al_(2)O_(3)-ZrO_(2)coating were studied.The results show that the Al_(2)O_(3)-ZrO_(2)-TiO_(2)composite powder was composed of t-ZrO_(2),a-Al_(2)O_(3),m-ZrO_(2)and rutile,while the Al_(2)O_(3)-ZrO_(2)-TiO_(2)composite coating consisted of t-ZrO_(2),a-Al_(2)O_(3)and c-Al_(2)O_(3).The diffraction peaks of TiO_(2)could not be detected in the Al_(2)O_(3)-ZrO_(2)-TiO_(2)coating even up to10 wt%TiO_(2)addition.The reason may be that TiO_(2)was dissolved in the amorphous phase or formed solid solution with c-Al_(2)O_(3)phase in the coating during cooling.Compared with the Al_(2)O_(3)-ZrO_(2)coating,the as-prepared Al_(2)O_(3)-ZrO_(2)-TiO_(2)coating had denser microstructure,less microcracks and more amorphous phases.The density of the Al_(2)O_(3)-ZrO_(2)-TiO_(2)coating increased with the increase of TiO_(2)content.The Al_(2)O_(3)-ZrO_(2)-10 wt%TiO_(2)coating had the most uniform and dense microstructure,possessed higher toughness,adhesive strength and wear resistance compared with the Al_(2)O_(3)-ZrO_(2)coating,which was due to its lower porosity and more uniform microstructure.
基金the National Natural Science Foundation of China(No.52072110)the Natural Science Foundation of Hebei Province,China(No.E2018202034).
文摘The Cr_(7)C_(3)−CrSi_(2)−Al_(2)O_(3)composite coatings were prepared by plasma spraying Cr_(7)C_(3)−CrSi_(2)−Al_(2)O_(3)and Al−Cr2O3−SiC composite powders,respectively.The microstructure,formation mechanism and properties of the two Cr_(7)C_(3)−CrSi_(2)−Al_(2)O_(3)composite coatings obtained by plasma spraying were investigated,and the reaction mechanism of the Al−Cr_(2)O_(3)−SiC system was explored.The results show that the coating obtained by plasma spraying Al−Cr_(2)O_(3)−SiC composite powders had thinner lamella and more tortuous interlayer interface,and the in-situ synthesized Cr_(7)C_(3),CrSi_(2)and Al_(2)O_(3)in the coating were all nano-crystallines.Compared with the Cr_(7)C_(3)−CrSi_(2)−Al_(2)O_(3)coating prepared by plasma spraying Cr_(7)C_(3)−CrSi_(2)−Al_(2)O_(3)composite powders,the plasma-sprayed Cr_(7)C_(3)−CrSi_(2)−Al_(2)O_(3)coating obtained from Al−Cr_(2)O_(3)−SiC composite powders had higher density,higher microhardness(increased by 20%),better fracture toughness and lower wear rate(reduced by 28%).
基金supported by the National Natural Science Foundation of China(Nos.52371063 and 52072110)the Natural Science Foundation of Hebei Province(No.E2018202034)+1 种基金the Central Funds Guiding the Local Science and Technology Development of Hebei Province(No.236Z7610G)the Graduate Innovation Project of Hebei Province(No.CXZZBS2022035).
文摘High porosity and high brittleness are the main reasons that limit the long-term service life of the alumina-titanium oxide composite coating.Herein,a metastable nanostructured aluminatitanium oxide composite coating with high density and high properties was synthesized by plasma spraying of TiO_(2)-Al composite powder.The main phases of the metastable nanostructured alumina-titanium oxide wereγ-Al_(2)O_(3),TiO and AlTiO_(2).The coating,as prepared,contains various metastable microstructures,such as fine-grained,intra-/inter-granular,and"self-locking"microstructures.These metastable microstruc-tures are important for the improvement of hardness and toughness of the coating.Compared with other alumina-based composite coatings,the metastable nanostructured aluminatitanium oxide composite coating showed the most impressive overall performance.The reinforcing and toughening mechanism of the metastable alumina-titanium oxide composite coating included fine grain strengthening and self-toughening of the metastable microstructure.
