ABSTRACT
HAP-Glass-alpha-Al2O3 gradient coating on alumina ceramics substrate was prepared by multi-layer slurry-dipping and sintering process, effects of the composition of the coating on the microstructure and adhesion strength of the gradient coating were studied. R2O-Al2O3-B2O3-SiO2 system glass with low softening temperature and thermal expansion was used in the gradient coating. The composition of the coating was varied from interface to surface layer, i.e. the HAP concentration increased and glass concentration decreased gradually from the under layer to the surface layer. A suitable amount superfine alpha-Al2O3 was added in the gradient coating to reinforce the bonding strength between the coating and substrate. The results show that the use of R2O-Al2O3-B2O3-SiO2 system glass is propitious to sintering the coating at low temperature and to combination between the coating and substrate. The addition of superfine alpha-Al2O3 can reinforce the bonding strength between the coating and substrate, the highest bonding strength is about 48.2 MPa.
Subject(s)
Adhesiveness , Aluminum Oxide , Chemistry , Ceramics , Chemistry , Coated Materials, Biocompatible , Chemistry , Durapatite , Chemistry , Glass , ChemistryABSTRACT
The effects of R2O-Al2O3-B2O3-SiO2 system glass and superfine alpha-Al2O3 on the sintering and phase transition of hydroxyapatite (HAP) ceramics were assessed. The results showed that alpha-Al2O3 impeded the sintering of HAP and raised the sintering temperature. When glass and alpha-Al2O3 were used together to reinforce HAP ceramics, better results could be obtained; the bending strength of multiphase HAP ceramics approached 106 MPa when 10% (wt) alpha-Al2O3 and 20%(wt) glass were used and sintered at 1200 for 1 h.
Subject(s)
Aluminum Oxide , Chemistry , Biocompatible Materials , Boron Compounds , Chemistry , Ceramics , Chemistry , Durapatite , Chemistry , Glass , Chemistry , Materials Testing , Silicon Dioxide , Chemistry , Tensile StrengthABSTRACT
Purpose The aim is to purify the peptide with antifu ngal activity from Aspergillus fumigatus culture fluid.Methods The pept ide was separated by ion exchange column chromatography and further purified by r everse phase HPLC,and the molecular weight was determined by tricine gel electro phoresis.Results A kind of peptide(FIP) with antifungal activit y wa s separated. The molecular weight was about 8 000. The detection result by MTT method showed significant antifungal activity of the peptide to 5 kinds of fung i.Conclusion The study provided a reliable basis for developin g drug and antiseptic.