Zirconia-toughened alumina powder (ZTA) is a high-performance ceramic powder

Zirconia-toughened Alumina Powder (ZTA) is a high-performance ceramic powder composed of alumina (Al₂O₃) and zirconia (ZrO₂). Its core strength lies in overcoming the fatal flaw of traditional alumina ceramics—being "hard and brittle"—through the toughening mechanism of zirconia phase transformation.

Alumina (Al₂O₃) – Provides high hardness, high wear resistance, high temperature resistance, and chemical corrosion resistance.

Toughening phase: Zirconia (ZrO₂) – Typically 10%~30% (commonly 15%/20%/25%), stabilized with yttrium oxide (Y₂O₃), etc.

A small amount of sintering aids (such as MgO, TiO₂) lowers the sintering temperature and refines the grain size.

1. Toughening through Induced Phase Transformation

1. After sintering, zirconium oxide is uniformly dispersed in the alumina matrix as a metastable tetragonal phase (t-ZrO₂).

2. When the ceramic is subjected to external force and cracks develop, the stress at the crack tip induces a martensitic phase transformation in the tetragonal zirconium oxide, transforming it into a stable monoclinic phase (m-ZrO₂).

3. This phase transformation is accompanied by a 3%–5% volume expansion, generating compressive stress at the crack tip. This compressive stress counteracts tensile stress, inhibits crack propagation, and absorbs a large amount of energy, thereby significantly improving toughness and impact resistance.

2. Powder Characteristics and Post-Sintering Properties
Zta Powder is typically submicron/nanometer in size (D50≈0.3~1.0μm), with high purity (≥99%), good dispersibility, and excellent flowability.

After sintering and densification (density > 99%), its performance is far superior to pure alumina:

3. Main Preparation Methods

1. Co-precipitation method: Aluminum salt and zirconium salt solutions are mixed and precipitated, then calcined to obtain nanocomposite powder. Uniform composition, high activity, mainstream process.

2. Mechanical mixing method: High-purity Al₂O₃ and ZrO₂ micro powders are ultra-finely ground. Low cost, simple process, but slightly inferior uniformity and dispersibility.

3. Sol-gel method: Chemical synthesis, extremely high purity, ultra-fine particle size, but high cost and low yield.

4. Spray drying granulation: The composite powder is made into free-flowing spherical particles, suitable for dry pressing and isostatic pressing.

4. Core Application Areas
ZTA perfectly balances high hardness, high toughness, and high wear resistance, making it widely used in demanding working conditions:

Wear-resistant structural components: Ceramic bearings, sealing rings, bushings, pump and valve parts, textile ceramic parts, sandblasting nozzles, with a lifespan far exceeding traditional alumina or cemented carbide.

Cutting tools: CNC cutting tools and inserts, high-speed cutting of cemented carbide, chilled cast iron, and wear-resistant cast iron.

Biomedical: Artificial joints, dental implants, orthopedic fixation components, with good biocompatibility, wear resistance, and corrosion resistance.

Petroleum/Chemical: Oil well logging nozzles, corrosion-resistant linings, valve seats, resistant to acids, alkalis, and particle erosion.

Precision/Electronics: Ceramic cutting tools (wire bonding machines), insulating bases, heat dissipation substrates, high precision, and good insulation.

Wear-resistant coatings/composite materials: Used as thermal spray powder to prepare wear-resistant and corrosion-resistant coatings for metal surfaces.

5. ZTA vs Pure Al₂O₃ vs Pure ZrO₂

vs Pure alumina (Al₂O₃): Significantly improved toughness, strength, and wear resistance; better impact and thermal shock resistance; less prone to cracking.

- vs Pure zirconia (ZrO₂): Higher hardness, better wear resistance, lower cost, higher thermal conductivity, and lower coefficient of thermal expansion, making it more suitable for high-temperature wear-resistant applications.

Zirconium oxide toughened alumina (ZTA) powder is a core raw material for advanced structural ceramics. Through microscopic composite design, it achieves a perfect combination of "rigidity (high hardness and wear resistance)" and "toughness (impact resistance)," far exceeding the performance of single alumina ceramics. It is a key material for upgrading and replacing materials in precision manufacturing, wear-resistant machinery, biomedicine, petrochemicals, and other fields.