title: [Study of relationship between powder-size gradation and mechanical properties of Zirconia toughened glass infiltrated nanometer-ceramic composite powder].
abstract: OBJECTIVE
  The fabrication of all-ceramic dental restorations is challenged by ceramics' relatively low flexural strength and intrinsic poor resistance to fracture. This paper aimed at investigating the relationships between powder-size gradation and mechanical properties of Zirconia toughened glass infiltrated nanometer-ceramic composite (Al(2)O(3)-nZrO(2)).
  
  
  METHODS
  Al(2)O(3)-nZrO(2) ceramics powder (W) was processed by combination methods of chemical co-precipitation and ball milling with addition of different powder-sized ZrO(2). Field-emission scanning electron microscopy was used to determine the particle size distribution and characterize the particle morphology of powders. The matrix compacts were made by slip-casting technique and sintered to 1,450 degrees C and flexural strength and the fracture toughness of them were measured.
  
  
  RESULTS
  1. The particle distribution of Al(2)O(3)-nZrO(2) ceramics powder ranges from 0.02 - 3.5 micro m and among them the superfine particles almost accounted for 20%. 2. The ceramic matrix samples with addition of nZrO(2) (W) showed much higher flexural strength (115.434 +/- 5.319) MPa and fracture toughness (2.04 +/- 0.10) MPa m(1/2) than those of pure Al(2)O(3) ceramics (62.763 +/- 7.220 MPa; 1.16 +/- 0.02 MPa m(1/2)).
  
  
  CONCLUSIONS
  The particle size of additive ZrO(2) may impose influences on mechanical properties of Al(2)O(3)-nZrO(2) ceramics matrix. Good homogeneity and reasonable powder-size gradation of ceramic powder can improve the mechanical properties of material.
authors.affiliation: Department of Prosthodontics, College of Stomatology, The Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Chai
authors.forename: Ling
authors.initials: L
authors.lastname: Xu
authors.forename: Yun-mao
authors.initials: YM
authors.lastname: Liao
authors.forename: Yong-lie
authors.initials: YL
authors.lastname: Chao
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry*; D006244:Hardness; D050997:Nanomedicine; D036103:Nanotechnology; D010316:Particle Size; D011208:Powders; D013718:Tensile Strength; D015040:Zirconium / Q000737:chemistry*
chemical_list: D011208:Powders; D003776:Dental Porcelain; D015040:Zirconium; D000537:Aluminum Oxide; C028541:zirconium oxide