Sliding wear of CaZrO3-MgO composites against ZrO2 and steel

Microstructural, mechanical and biological properties of hydroxyapatite - CaZrO3 biocomposites

“…Calcium zirconate presents a high chemical stability (stoichiometric congruent reaction at ~2365 °C) [37] and an excellent corrosion resistance against alkali environments [38], as well as a thermal barrier coating (TBC) [39,40]. Furthermore, the calcium zirconate can be sintered in an oxide atmosphere (low cost), and the resultant material displays surface properties (wear), modulus of elasticity and hardness that are compatible with its application in structural support [41][42][43]. Moreover, calcium zirconate displays a high affinity with titanium and its alloys, making it a potential candidate for biomedical applications [44,45].…”

Formation Mechanism of In Situ Intergranular CaZrO3 Phases in Sintered Magnesia Refractories

“…Generally, the CaZrO 3 phases are quite difficult to form in a natural environment owing to their high crystallization temperature and the high affinity of Zr for Si, resulting in the formation of zircon (ZrSiO 4 ) instead of CaZrO 3 phases. [11] Hence, to study the formation mechanism of these phases, the thermodynamic analysis of the intergranular phases in magnesia samples was presented first. Based on the chemical compositions of magnesite and EDS analysis of S1 above, it was believed that without the addition of ZrO 2 , the oxide impurities in magnesite (mainly SiO 2 and CaO) and periclase reacted with each other to form the intergranular CaO-MgO-SiO 2 phases.…”

“…[7][8][9] Meanwhile, CaZrO 3 is widely utilized in magnesia-based refractories as a second phase for improving their mechanical strength and resistance against basic phases and alkali attack. [10,11] The CaZrO 3 phase has high refractoriness (~2340°C), compatible with MgO, since these materials cannot react with each other, and do not form any liquid phases at temperatures lower than 2060°C. [11,12] Generally, the CaZrO 3 phase is introduced into magnesia-based refractories via two methods: (1) synthetic CaZrO 3 powders or aggregates are directly mixed with magnesia aggregates and sintered at high temperature, [13,14] and (2) zirconia (ZrO 2 ) or zircon (ZrSiO 4 ) is mixed with dolomite (MgCa(CO 3 ) 2 ) or MgO-CaO aggregates and sintered at high temperature.…”

“…[10,11] The CaZrO 3 phase has high refractoriness (~2340°C), compatible with MgO, since these materials cannot react with each other, and do not form any liquid phases at temperatures lower than 2060°C. [11,12] Generally, the CaZrO 3 phase is introduced into magnesia-based refractories via two methods: (1) synthetic CaZrO 3 powders or aggregates are directly mixed with magnesia aggregates and sintered at high temperature, [13,14] and (2) zirconia (ZrO 2 ) or zircon (ZrSiO 4 ) is mixed with dolomite (MgCa(CO 3 ) 2 ) or MgO-CaO aggregates and sintered at high temperature. [12,15,16] Nonetheless, for the first method, since CaZrO 3 is quite rare in nature and needs to be pre-synthesized, this method is limited by the high cost of purchasing synthetic CaZrO 3 .…”

“…[12,15,16] Nonetheless, for the first method, since CaZrO 3 is quite rare in nature and needs to be pre-synthesized, this method is limited by the high cost of purchasing synthetic CaZrO 3 . [11] Furthermore, for the second method, the introduction of CaO or SiO 2 may increase the formation of low-melting phases in magnesia aggregates, resulting in decreased performance. Meanwhile, it is known that natural magnesia aggregates may contain impurities such as CaO, SiO 2 , and trace amounts of Fe 2 O 3 (and/or FeO) or Al 2 O 3 , most of which are located at magnesia grain boundaries.…”