Chromium Oxynitride Multilayer Coating for High-Temperature Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing anti-oxidation layers applied to substrates exposed to high temperatures, such as those in gas turbines, are often thick and suffer from adhesion issues due to stress, and lack effective heat resistance.
Innovation Solution
A chromium-containing layer system is applied using vapor deposition methods like PVD and CVD, comprising a chromium nitride intermediate layer and an aluminum chromium oxide functional layer with a multilayer structure, which provides a thin, oxidation-resistant coating suitable for high-temperature applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If plasma spraying is used to apply anti-oxidation layers, then the layers can be applied relatively thickly, but they develop stresses that have a negative effect on adhesion
Solution Approach 1:
The coating is divided into multiple thin alternating layers of different materials (e.g., CrN, CrO, AlCrO) deposited in sequence. This segmentation into fine layers prevents stress accumulation that would occur in a single thick layer, while maintaining overall thickness for protection. Each thin layer adheres well to the substrate and previous layers without developing detrimental stresses.
Solution Approach 2:
The invention uses composite layer structures combining different chromium-based materials (chromium nitride, chromium oxide, aluminum chromium oxide) with complementary properties. The composite structure provides both adhesion (through materials like CrN) and oxidation resistance (through materials like CrO and AlCrO), while the alternating layers manage thermal stress to maintain bond integrity.
2Reliability
If oxidation-resistant materials are used for high-temperature substrates, then protection against oxidation is improved, but heat conduction properties may be adversely affected
Solution Approach 1:
Different layers in the coating system are assigned different functional qualities: chromium nitride layers provide adhesion and thermal conductivity, while chromium oxide and aluminum chromium oxide layers provide oxidation resistance. This local differentiation of properties allows the coating as a whole to achieve both oxidation protection and acceptable heat conduction without sacrificing one for the other.
Solution Approach 2:
The alternating composite structure combines materials with different thermal conductivities and oxidation resistance properties. The chromium nitride layers act as thermal pathways, while the chromium oxide and aluminum chromium oxide layers provide oxidation barriers. This composite approach balances heat conduction and oxidation protection.
3Loss of energy
If a thin protective layer is applied to maintain substrate properties, then heat conduction is improved, but the layer may not provide sufficient oxidation protection
Solution Approach 1:
The thin coating achieves sufficient oxidation protection through a composite structure where multiple layers work synergistically. The chromium oxide and aluminum chromium oxide layers provide oxidation barriers, while the chromium nitride layers provide adhesion and thermal pathways. The cumulative thickness of oxidation-resistant layers, though thin overall, provides adequate protection through the enhanced effectiveness of the composite structure.
Solution Approach 2:
The thin coating is segmented into multiple functional layers that maximize protection per unit thickness. The alternating structure of CrN/CrO/AlCrO layers creates a multi-barrier system against oxidation while maintaining thin overall dimensions for good heat conduction. Each layer contributes to the overall protection efficiency.
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 chromium-containing layer system offers improved adhesion and oxidation protection for substrates at high temperatures, maintaining structural integrity and reducing thermal stress, while allowing for precise control of layer thickness and composition for optimal performance.
Implementation Method 1
A chromium-containing layer system is applied using vapor deposition methods like PVD and CVD
Implementation Method 2
A chromium-containing layer system is applied using vapor deposition methods like PVD and CVD
Implementation Method 3
In the case of vaporization, spark vaporization is particularly preferred, in which material is locally vaporized from a target surface by means of an electric arc
Data Source
Figure 1
Figure 2
AI summary
The present invention relates to a chromium-based oxidation protection layer for substrates that are exposed to high temperatures, wherein the layer comprises a chromium-containing layer system, which comprises a base layer and a functional layer, and wherein the base layer is located between the substrate and the functional layer, and wherein the base layer contains at least mostly chromium nitride and the functional layer contains chromium oxide. The present invention further relates to a chromium-based oxidation protection layer for substrates that are exposed to high temperatures, wherein the layer comprises a chromium-containing layer system, which comprises a functional layer, wherein the functional layer has a multi-layer layer structure, which comprises individual layers A and B deposited in alternation, wherein the composition of the A individual layers differs from the composition of the B individual layers, and wherein the A individual layers contain at least mostly aluminium chromium nitride or preferably chromium nitride and the B individual layers contain at least mostly aluminium chromium oxide or chromium oxide or preferably aluminium chromium oxynitride or more preferably chromium oxynitride.