Facile preparation of BN coatings on graphite substrates and their binding strength. Issue 4 (15th February 2023)

• Record Type: Journal Article
• Authors: Li, Haixu; Liu, Xiaoguang; Jiang, Tiannan; Li, Tingxuan; Wang, Junsheng; Li, Bin; Xue, Wendong; Ren, Shubin; Sun, Jialin
• Is Part Of: Ceramics international. Volume 49:Issue 4(2023)
• Page Start: 6500
• Page End: 6507
• Publication Date: 2023-02-15
• Subjects: Al(H2PO4)3 -- MgAl2O4 -- Curing reaction -- BN coatings -- Binding strength; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2022.10.144
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: To decrease the curing temperature and achieve excellent binding strength of BN coatings on graphite substrates, a proper Al(H2 PO4 )3 binder has been carefully designed where MgAl2 O4 and poly vinyl alcohol (PVA) were used as the curing agent and the dispersant, respectively. XRD, SEM, TEM and DSC showed that the desired binding phase AlPO4 had been successfully obtained, where MgAl2 O4 and PVA worked synergistically to lower the curing temperature down to 70–100 °C and promote the formation of AlPO4 . Such optimized binder might have formed hydrogen bond with –NH2 and –OH groups on the BN flakes. It might also form hydrogen bond with-OH and –COOH groups on graphite substrates to ensure an optimal binding strength of 5.5 N (∼22 MPa) as suggested by the scratch tests. This work affords a better understanding on the curing chemistry of Al(H2 PO4 )3 and the binding mechanism between BN flakes, AlPO4 binding phases and graphite substrates.