Ammonia corrosion experiment

Ammonia Corrosion Testing Service – Comprehensive Evaluation of Material Resistance to Anhydrous and Aqueous Ammonia Environments for Canadian Industrial Applications

As an ISO/IEC 17025 accredited independent testing laboratory, we offer specialised ammonia corrosion testing services to manufacturers, engineering contractors, and asset operators serving the Canadian oil and gas, petrochemical, fertiliser production, refrigeration, mining, and power generation sectors. Ammonia – whether in anhydrous form (liquid or vapour) or aqueous solution (ammonium hydroxide) – is a highly corrosive agent that can cause stress corrosion cracking (SCC), general corrosion, pitting, and embrittlement of metallic materials, particularly carbon steels, stainless steels, copper alloys, and aluminium alloys. In Canada's diverse industrial landscape – from the Alberta oil sands and fertilizer plants in Saskatchewan to refrigeration systems in food processing facilities and cold storage warehouses – the integrity of equipment exposed to ammonia is critical for operational safety, environmental compliance, and asset longevity. Our test protocols evaluate the resistance of materials to ammonia-induced degradation under controlled temperature, pressure, and concentration conditions, using both accelerated laboratory and simulated service environments. All methods are aligned with ASTM, ISO, NACE, and CSA standards, including ASTM G31 (Immersion Corrosion), NACE TM0177 (SSC Testing), ISO 15156 (Materials for H₂S‑containing environments – adapted for ammonia), ASTM G123 (Stress Corrosion Cracking of Stainless Steels in Boiling Magnesium Chloride – modified for ammonia), and CSA Z245.15 (Steel pipelines for ammonia service). Our reports are recognised by Environment and Climate Change Canada (ECCC), Health Canada (for occupational safety), Transport Canada (for ammonia transport), and the Standards Council of Canada (SCC) for equipment registration, safety compliance, and quality assurance.

Materials and Components We Regularly Test for Ammonia Corrosion

Our ammonia corrosion test facilities accommodate a wide range of metallic materials, coatings, and welded assemblies. Typical test articles include:

• Carbon and low‑alloy steels – pipeline steels (CSA Z245.1, API 5L), pressure vessel steels (ASTM A516), and structural steels for ammonia storage and transport
• Stainless steels – austenitic (304L, 316L), duplex (2205, 2507), and super‑austenitic grades for ammonia service
• Nickel‑based alloys – Inconel®, Monel®, and Hastelloy®‑type alloys for high‑performance ammonia applications
• Copper and copper‑based alloys – brass, bronze, and cupronickel, which are susceptible to ammonia‑induced stress corrosion cracking
• Aluminium alloys – for refrigeration and cryogenic ammonia systems
• Welded joints and heat‑affected zones (HAZ) – including weld metal, fusion line, and HAZ for evaluating localised susceptibility to SCC
• Protective coatings and linings – epoxy, polyurethane, and rubber coatings applied to steel surfaces in ammonia service
• Fasteners, fittings, and valve components – for ammonia handling equipment
• Non‑metallic materials – elastomeric seals, gaskets, and polymeric linings for ammonia compatibility

Test Methods – Immersion, Salt Spray, and Cyclic Exposure in Ammonia Environments

• Full immersion corrosion test – ASTM G31 / ISO 11114 / GB/T 10124 – We immerse metallic specimens in aqueous ammonia solutions (typically 5‑28 % NH₃) or anhydrous liquid ammonia under controlled temperature (23 °C, 40 °C, 60 °C) and pressure (up to 2 MPa) for durations ranging from 24 hours to 90 days. The corrosion rate (in mm/year) is calculated from weight loss, and the pitting depth and morphology are assessed. For Canadian fertilizer and chemical plants, a corrosion rate of < 0.1 mm/year is typically required for carbon steel in dilute ammonia service.
• Vapour‑phase ammonia exposure test – for simulating conditions above liquid ammonia – We expose specimens to ammonia vapour (humidified or dry) at controlled temperatures and pressures, simulating the headspace environment of storage tanks and pipelines. The test evaluates the susceptibility to stress corrosion cracking and general corrosion from condensed ammonia or ammonium salts.
• Alternate immersion (wet/dry cycling) – for simulating service conditions with wetting and drying cycles – We cycle specimens between immersion in ammonia solution and exposure to air (or inert gas) to simulate the wetting and drying cycles that occur in ammonia refrigeration systems and storage tanks. The cycle frequency and the number of cycles are selected to match the expected service conditions.
• Pressurised ammonia exposure – for simulating high‑pressure ammonia systems – For components used in high‑pressure ammonia service (e.g., pipelines, compressors, and storage vessels), we perform exposure testing in a pressurised autoclave at up to 10 MPa and temperatures up to 150 °C. The test conditions are selected to match the service environment, and the specimens are evaluated for degradation and strength retention.
• Salt spray testing with ammonia – for simulating coastal and industrial environments – We combine salt spray (5 % NaCl) with ammonia vapour to simulate the corrosive conditions found in coastal ammonia storage facilities and offshore ammonia production platforms, particularly relevant for Atlantic Canadian and West Coast operations.
• Electrochemical corrosion testing – potentiodynamic polarisation and impedance spectroscopy – ASTM G5 / ISO 17475 – We perform potentiodynamic scans and electrochemical impedance spectroscopy (EIS) on metallic specimens in aqueous ammonia solutions to determine corrosion potential (Ecorr), pitting potential (Epit), passivation range, and charge‑transfer resistance. This technique is used to evaluate the susceptibility of stainless steels to pitting and to optimise the composition of alloys for ammonia service.

Stress Corrosion Cracking (SCC) and Hydrogen Embrittlement in Ammonia Environments

• Ammonia stress corrosion cracking (SCC) test – ASTM G123 / NACE TM0177 (adapted) – We apply a constant tensile stress (using U‑bend, C‑ring, or four‑point bent beam specimens) to metallic specimens immersed in ammonia solutions (anhydrous or aqueous) at controlled temperatures and concentrations. The time to cracking (in hours) is recorded. For carbon steel in anhydrous ammonia, the test is often performed with the addition of oxygen (0.1‑1 %) as a promoter, as is common in Canadian standards. A cracking resistance of ≥ 720 hours is typically required for critical ammonia handling equipment.
• Hydrogen embrittlement test – for materials exposed to ammonia with hydrogen sulfide or other promoters – For sour ammonia service (where H₂S is present), we perform hydrogen‑induced cracking (HIC) and sulphide stress cracking (SSC) tests according to NACE TM0284 and NACE TM0177, with modifications to include ammonia. The test evaluates the susceptibility to embrittlement under combined corrosive conditions.
• Slow strain rate testing (SSRT) – ASTM G129 / ISO 7539 – for assessing SCC susceptibility under dynamic conditions – We perform SSRT on tensile specimens in ammonia environments at a slow strain rate (10⁻⁶ s⁻¹) to assess the susceptibility to SCC and hydrogen embrittlement. The reduction in ductility and the fracture surface morphology are compared to tests performed in an inert environment.
• Fracture surface analysis – for identifying cracking mechanisms – ASTM E1508 / ISO 10543 – We examine the fracture surfaces of failed specimens under a scanning electron microscope (SEM) to identify the cracking mechanism (intergranular, transgranular, or mixed). The presence of secondary cracks, corrosion products, and inclusions is documented.

Environmental and Durability Testing – Simulating Canadian Climatic Conditions

• Temperature‑conditioned ammonia exposure – for simulating Canadian seasonal variations – We perform ammonia corrosion tests at sub‑zero temperatures (-20 °C, -40 °C) to simulate the winter conditions in the Canadian prairies and northern regions, and at elevated temperatures (40 °C, 60 °C) to simulate summer operations. The effect of temperature on the corrosion rate and SCC susceptibility is evaluated.
• Humidity and condensation testing – for simulating high‑humidity environments – We expose specimens to ammonia vapour at high humidity (95 % RH, 40 °C) to simulate the condensation conditions that occur in refrigerated ammonia systems and humid industrial environments. The corrosion rate and the risk of SCC are assessed.
• Thermal cycling – for simulating diurnal and seasonal temperature variations – IEC 60068‑2‑14 / GB/T 2423.22 – We subject specimens to repeated thermal cycles (e.g., -40 °C to +60 °C) while exposed to ammonia, to evaluate the effect of thermal stress on the material's resistance to cracking and corrosion.
• Corrosion under insulation (CUI) testing – for ammonia piping and vessels – We simulate corrosion under insulation by wrapping specimens in insulation material and exposing them to ammonia vapour and moisture, a common failure mechanism in Canadian ammonia plants. The time to pitting or SCC is recorded.
• UV and weathering testing – for outdoor ammonia storage and piping – ASTM G154 / ISO 4892‑3 – For outdoor equipment and coatings, we combine ammonia exposure with UV weathering to evaluate the degradation of protective coatings and the corrosion of underlying metal.

Regulatory Compliance and Canadian Standards – Supporting CSA, NACE, and Environment Canada Requirements

Our ammonia corrosion testing services are performed in accordance with the most widely used international and Canadian standards. The most commonly requested include:

• CSA Z245.15 – Steel pipelines for ammonia service – the primary Canadian standard for the design, fabrication, and testing of pipelines for anhydrous ammonia transport
• NACE TM0177 – Laboratory testing of metals for resistance to sulfide stress cracking and stress corrosion cracking – adapted for ammonia environments
• NACE TM0284 – Evaluation of pipeline and pressure vessel steels for resistance to hydrogen‑induced cracking – for sour ammonia service
• ISO 15156 – Petroleum and natural gas industries – Materials for use in H₂S‑containing environments – used as a reference for ammonia‑H₂S mixtures
• ASTM G31 – Standard Guide for Laboratory Immersion Corrosion Testing of Metals – for general corrosion testing
• ASTM G123 – Standard Test Method for Evaluating Stress‑Corrosion Cracking of Stainless Alloys with Different Nickel Content in Boiling Magnesium Chloride – adapted for ammonia SCC
• ASTM G5 – Standard Reference Test Method for Making Potentiodynamic Anodic Polarization Measurements – for electrochemical testing
• CSA B52 – Mechanical refrigeration code – for ammonia refrigeration systems – references corrosion and material compatibility requirements
• Health Canada – Occupational Health and Safety regulations – for ammonia exposure limits and equipment integrity
• Environment and Climate Change Canada (ECCC) – for ammonia emissions and environmental release prevention

Report Acceptance and Regulatory Recognition in Canada

All ammonia corrosion tests are conducted under our ISO/IEC 17025 accreditation, using calibrated autoclaves, electrochemical workstations, and analytical instruments, all traceable to national and international reference standards. Our comprehensive test reports include: a full description of the test material (grade, heat number, manufacturing process), a summary of the test conditions (ammonia concentration, temperature, pressure, test duration), a detailed description of the test results (corrosion rate, pitting depth, SCC susceptibility, HIC ratios), photographic and microscopic evidence of the corrosion damage, and a clear pass/fail verdict against your specified acceptance criteria or reference standard (e.g., CSA Z245.15, NACE TM0177, ASTM G31). We also provide an expanded uncertainty (k=2) for key measurements. These reports are widely accepted by Environment and Climate Change Canada (ECCC), Health Canada, Transport Canada, the Standards Council of Canada (SCC), and Canadian oil and gas, fertilizer, and refrigeration operators for material qualification, equipment registration, and quality assurance. Bilingual (English/French) versions are available to facilitate submissions to federal and provincial regulatory authorities and to support your global market access.