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  • Source : Press Release
  • Date : 2021-12-06
  • Companies : Tosoh Corp.

Tosoh Achieves World-First Technological Breakthroughs with Environmentally Friendly Zgaia Zirconia Powders

Tokyo, Japan—Tosoh Corporation is pleased to announce its newest addition to its line-up of zirconia powders, the Zgaia series. The company's redesign of the particle structure of conventional zirconia makes possible lower-temperature sintering, at 1,250°C, than the usual 1,500°C, thus, reducing carbon dioxide emissions in the manufacturing process.

Tosoh's Zgaia 1.5Y-HT is a world first. It features the lowest level of yttrium oxide (Y2O3) content, of only 1.5 mol%, ever achieved in zirconia, while exhibiting both superior bending strength and fracture toughness. Furthermore, Tosoh will also start introducing to customers the Zgaia series' 3Y-LD grade, which features high durability owed to past efforts of Tosoh R&D.

The mechanism behind Zgaia 1.5Y-HT's fracture toughness, meanwhile, is being investigated by the Next Generation Zirconia Social Cooperation Program, which involves the University of Tokyo and Tosoh Corporation and other private companies. The participants in this research program plan to issue a joint announcement soon to inform customers of that mechanism. The company is also considering starting the mass production of its Zgaia series in tandem with the announcements regarding the mechanism of Zgaia 1.5Y-HT's fracture toughness.

Tosoh was the world's first company to mass produce zirconia, and it maintains its position as the world's leading manufacturer in the field of fine ceramics. The company continues to focus on developing innovative technologies.

1. Features of the Zgaia series overall

A) A redesigned particle structure makes possible low-temperature sintering.

B) A proprietary manufacturing method ensures uniform Y2O3 distribution.

A Y2O3 content of 1.5 mol% is sufficient for sintering Zgaia 1.5Y-HT.
A uniform microstructure of sintered particles suppresses hydrothermal degradation in Zgaia 3Y-LD.

2. Features of the Zgaia series by grade

A) Zgaia 1.5Y-HT

A Y2O3 content lower than previously capable of being sintered enables the fracture toughness and bending strength not possible with conventional zirconia.

 

Zgaia 1.5Y-HT

TZ-3YSB-E

(Conventional Tosoh product)

Amount of Y2O3 added (mol%)

1.5

3

Sintering temperature (°C)

1,250

1,350

1,500

3P bending strength (MPa)

1,200

1,200

1,500

Fracture toughness (MPa-m1/2)*

8.5

10.1

4.7

Monoclinic ratio after autoclave test 140°C × 24 hours

33

67

73


B) Zgaia 3Y-LD

A four-year period of accelerated degradation tests where the sintered material was immersed in 140°C water resulted in almost no deterioration and confirmed Zgaia 3Y-LD's remarkable durability.

 

Zgaia 3Y-LD

Amount of Y2O3 added (mol%)

3

Amount of AI2O3 added (wt%)

0.25

Sintering temperature (°C)

1,250

3P bending strength (MPa)

1,000

Fracture toughness (MPa-m1/2)*

3.9

Monoclinic ratio after autoclave test

140°C × 100 hours

140°C × 1,500 days

 

 0.2

2.5



*This value is the result of an evaluation by Tosoh and is not guaranteed. Fracture toughness was measured by the JIS R1607 single-edged pre-cracked beam (SEPB) method.

For more information, please contact:

Tosoh Corporation: [email protected]
Tosoh USA, Inc.: [email protected]
Tosoh Europe B.V.: [email protected]