title: [Effect of two-step sintering method on properties of zirconia ceramic].
abstract: OBJECTIVE
  To study the influence of two-step sintering method on the sintering property, mechanical properties and microstructure of zirconia ceramic.
  
  
  RESULTS
  The nano-size zirconia powder were compacted and divided into two groups, one group for one-step sintering method, another group for two-step sintering method. All samples sintered at different temperature. The relative density, three-bend strength, HV hardness, fracture toughness and microstructure of sintered block were investigated.
  
  
  RESULTS
  Two-step sintering method influenced the sintering property and mechanical properties of zirconia ceramic. The maximal relative density was 98.49% at 900 degrees C/1,450 degrees C sintering temperature. There were significant difference of mechanical properties between one-step sintering and two-step sintering, the three-bend strength and fracture toughness declined, hardness increased at two-step sintering. The three-bend strength, HV hardness and fracture toughness reached to maximum value as 1,059.08 MPa +/- 75.24 MPa, 1,377.00 MPa +/- 16.37 MPa and 5.92 MPa x m1/2 +/- 0.37 MPa x m1/2 at 900 degrees C/1,450 degrees C sintering temperature respectively. Microscopy revealed the relationship between the porosity and shapes of grains was correlated to strength of the zirconia ceramics.
  
  
  CONCLUSIONS
  Despite of the two-step sintering method influences the properties of zirconia, it also is a promising esthetic all-ceramic dental material.
authors.affiliation: Department of Prosthodontics, Shanghai Ninth People's Hospital, Shanghai Jiaotong University, Shanghai 200011, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Huang
authors.forename: Bin
authors.initials: B
authors.lastname: Wei
authors.forename: Fu-Qiang
authors.initials: FQ
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Sun
authors.forename: Lian
authors.initials: L
authors.lastname: Gao
mesh_terms: D002516:Ceramics; D003764:Dental Materials; D003776:Dental Porcelain; D006244:Hardness; D008422:Materials Testing; D016062:Porosity; D013696:Temperature; D015040:Zirconium
chemical_list: D003764:Dental Materials; D003776:Dental Porcelain; D015040:Zirconium; C028541:zirconium oxide