Zinc Chloride Flux
Zinc Chloride Flux (ZnCl2) is a white, crystalline, highly soluble inorganic salt used as a powerful active chemical flux. Its primary function is to chemically clean metal surfaces by dissolving the tenacious oxide layers (dross, rust, or scale) that prevent good wetting and bonding during metal joining or coating processes. It is one of the oldest and most aggressive fluxes in use today, typically applied as an aqueous solution or as a component in a paste/powder.
Main Composition and Function
ZnCl2 is a strong Lewis acid that attacks and dissolves metal oxides even at relatively low temperatures.
| COMPONENT | CHEMICAL FORMULA | PROPERTY HIGHLIGHT |
| Zinc Chloride | ZnCl2 | Strong Lewis acid, highly hygroscopic (absorbs water), and corrosive. |
| Active Flux | ZnCl2 / HCl (when heated) | Aggressive chemical attack on metal oxides (MxOy). |
| CLASSIFICATION | MELTING POINT | PRIMARY APPLICATION FOCUS |
| Active Chemical Flux | 290°C (554 F) | Surface preparation for soldering, brazing, and hot-dip galvanizing. |
Key Performance Metrics
| PROPERTY | TYPICAL PERFORMANCE | MECHANISM OF ADVANTAGE |
| Oxide Removal | EXTREME | Effectively removes heavy layers of difficult-to-dissolve oxides. |
| Hygroscopicity | HIGH | Absorbs moisture from the air, which can aid in the dissolution process but complicates storage. |
| Wetting Promotion | EXCELLENT | Cleans the base metal surface, allowing the solder or zinc coating to spread evenly and bond strongly. |
Zinc Chloride Flux
Mechanism of Action
When heated or applied to a wet surface, ZnCl2 hydrolyzes and decomposes to release hydrochloric acid (HCl), which is the active oxide-dissolving agent:
The released HCl attacks the metal oxides (MxOy) on the surface, converting them into volatile or soluble chloride salts that are immediately carried away by the molten solder or coating. The clean metal surface is then ready for bonding.
Applications
- Hot-Dip Galvanizing: In the galvanizing industry, ZnCl2 is often combined with NH4Cl (Ammonium Chloride) to form a double salt flux. This flux is applied to the iron or steel article just before dipping into the molten zinc bath. It chemically cleans the last traces of iron oxide and ensures a continuous, high-quality metallic bond between the steel and the zinc coating.
- Soldering and Tinning: Used as a highly active flux for soldering difficult-to-solder materials, especially iron and steel. It is commonly found in acid-core solder or aggressive liquid fluxes.
- Brazing: Used in some non-ferrous and ferrous brazing applications where strong chemical cleaning is required.
Technical Guidance and Limitations
- Corrosivity (MAJOR Limitation): Because ZnCl2 is highly acidic and corrosive, its residues must be thoroughly cleaned from the joined surfaces immediately after the process is complete. If residues are left behind, they will continue to attack the base metal, leading to joint failure, premature corrosion, and component damage. This is why it is often avoided for electrical or electronic soldering in favor of less aggressive fluxes.
- Fumes: The use of ZnCl2 flux generates acidic and toxic fumes (mostly HCl and other chlorides) that require robust ventilation and fume extraction to ensure operator safety and environmental compliance.
- Storage: Due to its high hygroscopicity, solid ZnCl2 must be stored in airtight, moisture-proof containers.
✨ Customization Services
We offer product customization services, allowing you to tailor the appearance, dimensions, or specific markings of items like refractory shapes or bricks. This includes options for incorporating specific geometric requirements to ensure seamless integration into your process systems.
🔬 Sampling for Testing & Validation
Free product samples are available for thorough testing and validation. This allows you to confirm the quality, compatibility, and performance of our materials—such as specific bricks, castables, or raw materials—before committing to a full order.
💡 Expertise in Refractory Solutions
Leverage our deep expertise to receive detailed, application-specific refractory solutions. We move beyond just selling products by providing comprehensive plans that encompass material selection, installation guidance, and performance optimization to maximize the lifespan and efficiency of your high-temperature processes.
Rabatec products are exclusively manufactured in facilities that have achieved rigorous ISO certifications across Quality (ISO 9001), Environmental Management, and Occupational Health & Safety. This commitment ensures every product, from refractory bricks to specialized equipment, meets the highest global benchmarks for performance, sustainability, and workplace safety.
📦 Logistics Excellence: Shipping, Packaging, and Marking
Minimizing Risk: We manage all logistics to minimize handling touchpoints and transit shock. Our carriers are pre-vetted for their experience in transporting heavy, fragile, and sensitive industrial materials.
Traceability: Every shipment includes comprehensive documentation and tracking information, providing end-to-end visibility and ensuring precise delivery coordination for your site.
Protection is Paramount: Our packaging strictly follows industry standards to prevent damage, corner chipping, and moisture absorption—especially critical for materials like Basic Refractory Bricks and Refractory Mortars & Mixes.
Robust Palletization: Products are secured on fumigated, high-strength export pallets (e.g., 1100x950mm or similar sturdy dimensions) using heavy-duty strapping and durable protective wrapping (polyethylene sheeting, cardboard, etc.) to withstand long-distance travel and multiple loadings.
Moisture Control: Sensitive materials are protected with appropriate sealing and, where necessary, desiccants or moisture-vapor proof enclosures to maintain the product's integrity until installation.
Clear Identification: All outer packaging is clearly marked on multiple sides with large, legible text for immediate identification and safe handling.
Full Traceability: Markings include all essential data points: Product Name, Quality Grade, Batch Number, Quantity, Net/Gross Weight, Order Number, and the Final Destination/Construction Area. This ensures every pallet can be accounted for and correctly staged upon arrival.
Safety & Compliance: We adhere to all regulatory requirements for marking, labeling, and placarding—especially for any items classified as Dangerous Goods—to ensure full compliance with international and domestic transport regulations.
❓ Frequently Asked Questions (FAQ)
Question | Elaborated Answer |
Q: What is the Refractoriness Under Load (RUL) of your refractories? | A: Refractoriness Under Load (RUL) is a critical property that defines the maximum temperature our materials can withstand while under compressive stress before deforming (softening). Since we offer a wide range of materials—from Alumina-Silicate Bricks to high-performance Silicon Carbide Bricks—the RUL varies significantly. For specific product data, please refer to the product data sheet or submit a quote request for the material you are interested in. |
Q: Where are the Rabatec refractories and materials produced? | A: Our products are primarily sourced from specialized manufacturing plants in China. Crucially, these facilities have all undergone rigorous audits and achieved comprehensive ISO certifications (Quality, Environment, and Safety), ensuring that production adheres to the highest global standards for consistency and performance. |
Q: What refractory materials does the company offer? | A: We supply a comprehensive portfolio of advanced refractory solutions, including: Shaped Products: Alumina & Silica Bricks, Basic & Specialized Bricks (e.g., Magnesia), SiC & Structural Ceramics, and Precast Shapes. Monolithic Products: Refractory Castables, Mixes & Mortars. Insulation: Insulation Fibre and High-Performance Insulation Products. |
Q: How should I choose the appropriate refractory material for my application? | A: Selecting the correct refractory is paramount to process efficiency. The choice depends on three key factors: 1. Operating Environment: Maximum process temperature and thermal cycling (shock). 2. Chemical Attack: Type of slag, molten metal, or corrosive gas being handled (acidic, neutral, or basic). 3. Mechanical Stress: Abrasion, erosion, and static load requirements. We recommend utilizing our detailed refractory solutions service to consult with our engineers for an optimized, application-specific recommendation. |
Q: Which monolithic material should I choose when patching an existing lining? | A: For patching and minor repairs, the ideal monolithic material depends on the parent lining material, the patching depth, and the need for a rapid return to service. Common choices include: Refractory Mortars & Mixes (for minor joints/surfaces) or Plastic Refractories (for areas requiring physical compaction). Always choose a patch material chemically compatible with the existing lining to ensure proper bonding and service life. |
Q: Can I receive product samples before placing a major order? | A: Yes. We gladly provide product samples for your internal testing and validation purposes. This ensures you can confirm the quality, composition, and fit of the material—such as our Refractory Castables or Alumina-Silicate Bricks—in your specific operational environment before committing to a bulk purchase. |
Q: Do you provide certifications to verify material quality? | A: Absolutely. We provide product-related inspection certificates and quality assurance documentation upon request. This verifies that your order has passed all internal quality control checks and meets the required material specifications and industry standards. |
Q: What measures are taken for product protection during transport? | A: We ensure quick, reliable transport by using robust, industrial packaging that strictly follows industry standards. This includes high-strength palletization, heavy-duty strapping, and weather-resistant wrapping to protect fragile items like bricks and mixes from corner chipping, mechanical damage, and moisture during transit. |
