Titanium Alloy Surface Hardening via Solid Carburizing and Gas Co-infiltration
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Solution Overview
Problem
Titanium alloy has low superficial hardness and wear resistance, limiting its application in high-end equipment components, and existing surface modification methods like coating and chemical heat treatment struggle to achieve thick, non-brittle surface layers.
Innovation Solution
A method involving solid carburizing with a combination of charcoal powder, barium carbonate, calcium carbonate, barium acetate, urea, and cerium carbonate, followed by gas co-infiltration using ammonia, air, and acetylene, to create a thick, hardened surface layer with improved wear resistance and reduced brittleness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If chemical heat treatment is used to thicken the surface layer, then the thickness increases, but the brittleness increases significantly
Solution Approach 1:
The patent changes the chemical composition parameters of the surface layer by introducing multiple alloying elements (B, Si, Ca, Al, Ti) in controlled proportions. This creates a complex compound structure that achieves thickness without the excessive brittleness associated with conventional chemical heat treatment, resolving the contradiction between thickness and brittleness
Solution Approach 2:
The surface layer is designed as a composite structure containing multiple phases and alloying elements. The combination of boron, silicon, calcium, aluminum, and titanium creates a composite material system that provides both thickness and controlled mechanical properties, avoiding the brittleness problem of single-phase thick layers
2Strength
If coating technology or ion implantation is used, then surface hardness is improved, but the surface treatment layer thickness is limited and cannot reach several hundred microns
Solution Approach 1:
The patent merges multiple surface treatment mechanisms into a single process. It combines chemical heat treatment with alloying element diffusion, creating a unified treatment that simultaneously achieves both high surface hardness and thick surface layer (several hundred microns), overcoming the thickness limitation of conventional coating and ion implantation methods
3Weight of moving object
If titanium alloy replaces steel, then weight reduction is achieved, but the superficial hardness and wear resistance are insufficient
Solution Approach 1:
The patent applies local quality modification by creating a specialized surface layer with enhanced properties while maintaining the bulk titanium alloy's lightweight characteristics. The surface layer contains concentrated alloying elements (B, Si, Ca, Al, Ti) that provide high hardness and wear resistance locally, while the underlying titanium alloy structure retains its weight advantage, thus resolving the contradiction between weight reduction and surface performance
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 method achieves a surface hardened layer of several hundred microns with significantly lower brittleness than conventional chemical heat treatment, enhancing wear resistance and supporting the application of titanium alloy in tools, molds, gears, and bearings.
Implementation Method 1
the more active carbon atoms produced by decomposition
Implementation Method 2
carburizing treatment...active carbon atoms produced by decomposition
Implementation Method 3
gas co-infiltration using ammonia, air, and acetylene
Implementation Method 4
gas co-infiltration to achieve surface modification...nitrogen and carbon elements
Implementation Method 5
carburizing treatment...heating to facilitate diffusion
Implementation Method 6
heating the furnace at a heating rate of 20 degree Celsius per minute to a target temperature
Data Source
AI summary
Disclosed is a method for surface-modifying titanium alloy, comprising the following steps: carburizing titanium alloy in solid carburizing agent A and solid carburizing agent B, and then performing gas co-infiltration to realize surface modification treatment of titanium alloy; the solid carburizing agent A includes raw materials of charcoal powder a, barium carbonate, calcium carbonate, barium acetate, urea and cerium carbonate, and the solid carburizing agent B includes raw materials of charcoal powder b, barium carbonate, calcium carbonate and cerium carbonate; and the gases used in the gas co-infiltration are ammonia, air and acetylene.