Three kinds of new type solid strong acid catalysts S2O 2-8/ZrO2-Al2O3-M2O3（M=Cr,Ce,La） were prepared. Their crystal structure, surface area, acid strength and sulfur content were determined by means of XRD, BET, fl...Three kinds of new type solid strong acid catalysts S2O 2-8/ZrO2-Al2O3-M2O3（M=Cr,Ce,La） were prepared. Their crystal structure, surface area, acid strength and sulfur content were determined by means of XRD, BET, flow Hammett indicator method and chemical analysis. Their catalytic activities in esterification reaction of acetic acid with n-butanol were studied. The results showed that ZrO2 in the catalysts mainly in tetragonal phase and few in monoclinic phase. The tetragonal phase of ZrO2 and S2O 2-8 are the key factors that guarantee the catalytic activity. Incorporation of appropriate amounts of metallic oxides（Cr2O3,Ce2O3,La2O3） into the catalyst favors the stabilization of sulfur species and surface area, which increase the activity sites on the catalyst. The experimental results showed that three catalysts S2O 2-8/ZrO2-Al2O3（2%）-M2O3（1%）（M=Cr,Ce,La） had higher catalytic activity in mentioned esterification, with the conversion of acetic acid reached 96.8%, 95.7% and 96.1%, respectively. The preparation condition of the catalysts showed great influence on the catalytic activity.展开更多
The polarizabilities of ZrO_2 and SiO_2 nanoparticles were studied on the basis of hyper Rayleigh scattering measurement.It was found that the polarizability of system depended on both particle size and concentration.
The friction and wear properties of ZrO2 and Al2O3 cooperatively toughened mullite composites-mullite/ZrO2/Al2O3（MZA） were studied. The tribological tests were performed in a line-reciprocating tribometer using a GC...The friction and wear properties of ZrO2 and Al2O3 cooperatively toughened mullite composites-mullite/ZrO2/Al2O3（MZA） were studied. The tribological tests were performed in a line-reciprocating tribometer using a GCr15 steel ball on a MZA disk under different dry reciprocating sliding conditions at room temperature. A wide range of normal loads and sliding speeds were chosen to investigate the relationship between the wear mechanisms of MZA and the testing conditions. The wear mechanism diagram of MZA is constructed, it contains two typical regions. It suggests that the wear mechanisms of MZA in each of the region change from one to another depending on the wear conditions. In the mild wear region, the wear rate of MZA is 10-6 mm3/m, and the wear mechanism of MZA is plastic deformation accompanied by a little micro-cracking. In the severe wear region, the wear rate of MZA is 10-5 mm3/m and the dominant wear mechanism in this region is brittle fracture.展开更多
文摘Three kinds of new type solid strong acid catalysts S2O 2-8/ZrO2-Al2O3-M2O3（M=Cr,Ce,La） were prepared. Their crystal structure, surface area, acid strength and sulfur content were determined by means of XRD, BET, flow Hammett indicator method and chemical analysis. Their catalytic activities in esterification reaction of acetic acid with n-butanol were studied. The results showed that ZrO2 in the catalysts mainly in tetragonal phase and few in monoclinic phase. The tetragonal phase of ZrO2 and S2O 2-8 are the key factors that guarantee the catalytic activity. Incorporation of appropriate amounts of metallic oxides（Cr2O3,Ce2O3,La2O3） into the catalyst favors the stabilization of sulfur species and surface area, which increase the activity sites on the catalyst. The experimental results showed that three catalysts S2O 2-8/ZrO2-Al2O3（2%）-M2O3（1%）（M=Cr,Ce,La） had higher catalytic activity in mentioned esterification, with the conversion of acetic acid reached 96.8%, 95.7% and 96.1%, respectively. The preparation condition of the catalysts showed great influence on the catalytic activity.
文摘The polarizabilities of ZrO_2 and SiO_2 nanoparticles were studied on the basis of hyper Rayleigh scattering measurement.It was found that the polarizability of system depended on both particle size and concentration.
基金Project supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars Education Minis try China
文摘The friction and wear properties of ZrO2 and Al2O3 cooperatively toughened mullite composites-mullite/ZrO2/Al2O3（MZA） were studied. The tribological tests were performed in a line-reciprocating tribometer using a GCr15 steel ball on a MZA disk under different dry reciprocating sliding conditions at room temperature. A wide range of normal loads and sliding speeds were chosen to investigate the relationship between the wear mechanisms of MZA and the testing conditions. The wear mechanism diagram of MZA is constructed, it contains two typical regions. It suggests that the wear mechanisms of MZA in each of the region change from one to another depending on the wear conditions. In the mild wear region, the wear rate of MZA is 10-6 mm3/m, and the wear mechanism of MZA is plastic deformation accompanied by a little micro-cracking. In the severe wear region, the wear rate of MZA is 10-5 mm3/m and the dominant wear mechanism in this region is brittle fracture.
