Intergranular Oxidation Testing (IGO) Metallography Services for Aerospace & Oil & Gas 

Detect Grain-Boundary Oxygen Damage Accredited, Defensible, and Delivered Fast 

Why Intergranular Oxidation Testing Matters 

In Ni-base superalloys, stainless steels, low-alloy steels, and Ti alloys near hot gas paths, IGO creates embrittled boundary networks that: 

• Accelerate fatigue crack initiation at edges, holes, and coating interfaces. 

• Reduce creep/rupture margins and weld HAZ durability. 

• Compromise bond-coat/adherent coating performance and repairability. 
  Quantifying IGO depth (max/average) and affected-zone width verifies heat-treat atmosphere quality, validates stock-removal allowances, and supports OEM/FAA expectations for hot-section hardware and high-temperature service parts. 

AADFW’s Approach: Precision, Speed, and Proof 

• Accredited & precise: Metallography performed under ISO/IEC 17025 with disciplined prep, calibrated optics, and documented measurement procedures. 

• Faster results: Alloy-specific prep/etch routes and decision-ready photo plates compress lead times without sacrificing rigor. 

• Trusted by engineers: Clear acceptance call-outs tied to your print/spec, location maps, and expert mechanism narratives that stand up to audits. 

Intergranular Oxidation Service Capabilities 

• Targeted Sectioning & Mounting 
  Non-thermal sectioning at edges, cooling holes, coating interfaces, weld toes/HAZ, grain-flow breaks, and specified orientations (L/T/S). Orientation marks ensure repeatable fields. 

• Artifact-Free Preparation & Micro-Etching 
  Grinding/polishing per ASTM E3; alloy-appropriate etchants per ASTM E407 to reveal boundary penetration and differentiate oxide, internal oxidation, and depletion zones. 

• Ni-base/Co-base: Glyceregia/Vilella variants to delineate IGO and γ/γ′ changes. 

• Stainless steels: Oxalic screen (structure only) plus glyceregia for carbides/σ; used to separate sensitization from true IGO. 

• Steels/Ti (as specified): Etches tuned to expose boundary oxygen ingress or alpha-case adjacency. 

• Depth & Affected-Zone Measurement 
  Quantify IGO depth (max/avg) from surface to unaffected matrix; measure depleted/intergranularly attacked zone width with calibrated scale bars and overlays. Optional field counts (N) and statistics per drawing. 

• Microhardness & Gradient Mapping (as required) 
  Vickers/Knoop traverses (ASTM E384 / E92) across the IGO layer and substrate to document embrittlement gradients and confirm removal allowances. 

• Coating & Repair Interface Studies 
  Cross-sections through bond-coats, aluminides, and overlay coatings to evaluate IGO at the coating/substrate line and its impact on adhesion or refurbishment stock removal. 

• Reporting & Traceability (Audit-Ready) 
  Photo plates with etchant/time & magnification, location maps, measurement tables (max/avg depths), hardness profiles, acceptance summary (go/no-go), and instrument/calibration references tied to heat/lot and PO. 

Industries We Support 

• Aerospace: Coated airfoils, combustor/duct hardware, and welded CRAs, aligned to OEM/FAA expectations. 

• Oil & Gas: High-temperature valves, turbines, furnaces/CRAs, and weld overlays where oxidizing environments and thermal cycling drive IGO risk. 

• Defense & Advanced Manufacturing: Mission-critical hot-zone parts (including AM builds) requiring verified surface integrity and removal allowances. 
  Trusted by engineers and QC managers across mission-critical industries. 

Accreditations & Standards Compliance 

AADFW operates to ISO/IEC 17025 and supports Nadcap-driven program requirements. We execute metallography to methods on our accredited scope and applicable specifications, including: 

• ASTM E3 (metallographic specimen preparation) 

• ASTM E407 (micro-etching) 

• ASTM E384 / E92 (microhardness for gradient profiling) 

• ASTM E112 (grain size, when corroboration is requested) 

• Optional corrosion corroboration (when specified): ASTM A262 practices for stainless or ASTM G28 for Ni-base—reported alongside IGO microstructure 

• OEM/AMS/customer criteria for IGO/stock-removal—matched exactly when cited in purchase documents 

Why Engineers Choose AADFW 

• Accredited & audit-ready IGO evaluations with calibrated imaging and defensible measurements. 

• Faster turnaround that keeps hot-section qualifications and MRB gates on schedule. 

• Trusted partner to aerospace and oil & gas QA teams. 

• Expert metallurgists who turn micrographs and maps into clear go/no-go decisions and actionable process or removal guidance. 

Request a Quote for Intergranular Oxidation Testing 

Protect fatigue life and hot-zone reliability with verified IGO depth and severity. Request a Quote to schedule IGO metallography today.