Calcium-Modified Copper Vanadium Oxide for Negative Thermal Expansion

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Solution Overview

Problem

Copper vanadium composite oxides exhibit low linear coefficients of thermal expansion and require further improvement in negative thermal expansion characteristics, particularly for industrial applications requiring better water resistance and lower-cost raw materials.

Innovation Solution

A copper vanadium composite oxide is modified by incorporating calcium (Ca) to enhance its negative thermal expansion properties, with a specific composition defined by the formula CuxCayVzOt, where 0<x<2.50, 0<y<2.00, 1.70≤z≤2.30, 6.00≤t≤9.00, and 1.00≤x+y≤3.00, and optionally incorporating phosphorus, to achieve a thermal expansion coefficient of −10.0×10−6/K or less.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If copper vanadium composite oxide is used, then negative thermal expansion characteristics are improved, but water resistance is insufficient

Engineering Contradiction:

Improvenegative thermal expansion characteristicsVSAvoidwater resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention uses a composite material system consisting of copper vanadium composite oxide particles combined with a water-resistant resin material. The resin forms a protective matrix that encapsulates the oxide particles, providing water resistance while preserving the negative thermal expansion properties of the oxide. This composite structure resolves the contradiction by combining materials with complementary properties.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The water-resistant resin is applied specifically to the surface and interstitial regions of the copper vanadium composite oxide particles, providing localized protection against water infiltration. This allows the core oxide particles to maintain their intrinsic negative thermal expansion characteristics while the resin-coated regions provide the necessary water resistance.

Inventive Principle:

Principle #3Local quality

2Reliability

If copper vanadium composite oxide is used, then negative thermal expansion characteristics are improved, but raw material cost increases

Engineering Contradiction:

Improvenegative thermal expansion characteristicsVSAvoidraw material cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention optimizes the composition parameters of the copper vanadium composite oxide, specifically controlling the ratios of copper, vanadium, and calcium oxides to achieve the desired negative thermal expansion characteristics while using cost-effective raw materials. By adjusting compositional parameters within specific ranges, the invention balances performance requirements with manufacturing cost considerations.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The modified copper vanadium composite oxide demonstrates improved negative thermal expansion characteristics, with a coefficient of thermal expansion as low as −10.0×10−6/K, suitable for use in composite materials with positive thermal expansion materials to achieve low or zero thermal expansion.

Implementation Method 1

materials that contract upon heating (hereinafter occasionally referred to as 'negative thermal expansion materials') are also known

Methodology Applied

Scientific EffectNegative thermal expansion: Negative Thermal Expansion

Data Source

PatentUS12590012B2Negative thermal expansion material and composite material

Publication Date: 2026.03.31 NIPPON CHEMICAL IND CO LTD

AI summary

An object of the present invention is to provide a negative thermal expansion material having better negative thermal expansion characteristics. The present invention is a negative thermal expansion material, comprising a copper vanadium composite oxide represented by the following general formula (1): CuxCayVzOt. In the general formula (1), 0<x<2.50, 0<y<2.00, 1.70≤z≤2.30, 6.00≤t≤9.00, and 1.00≤x+y≤3.00.