Recently, I’ve fielded several requests to clarify the distinction between “halide-free” and “halogen-free.” Both terms apply to the composition of soldering fluxes in the electronics assembly industry. While some may use the terms interchangeably without any repercussions, the definitions are not synonymous. This topic can get a bit confusing, so in this article, I’ll outline the difference between halides and halogens in the context of both industry standards and general chemistry.
알아야 할 사항
Understanding these terms in the context of industry standards is crucial. For a standardized definition of “halide-free,” we refer to J-STD-004 (Rev. C). J-STD-004C defines “halide-free” as a flux that contains less than 0.05% of combined halide ions (F-, Cl-, Br-, I-) as a weight percentage of the solid portion of the flux. The analytical test method “ion chromatography” is performed on flux in the unheated state. The halide content of a flux is designated by the final character in the flux classification: 0 for halide-free, 1 for halide-containing.
On the other hand, IEC 61249 defines “halogen-free” as a material with residue that contains less than 0.09% of chlorine (all forms), less than 0.09% of bromine (all forms), and less than 0.15% of chlorine and bromine combined. The analytical test method (per J-STD-004C) “bomb calorimetry,” followed by ion chromatography, is performed on flux residue in the final reflowed residue form. The halogen test is optional, and there is no standardized character designation.
알아야 하는 이유
할로겐화물은 솔더를 부식시킬 수 있는 잠재력을 가지고 있어 전기적 바이어스와 습기가 있는 경우 수지상 성장을 일으킬 수 있기 때문에 할로겐화물의 농도를 모니터링합니다. 무청정 제품이 J-STD-004 SIR 및 ECM 테스트를 통과하고 올바르게 사용되는 경우 이는 문제가 되지 않습니다. 세척해야 하는 플럭스 잔류물(수용성)의 경우, 철저하고 효과적인 세척 프로세스를 사용하면 부식을 방지할 수 있습니다. 할라이드 함유 플럭스는 본질적으로 어셈블리에 유해하지 않다는 점을 다시 한 번 강조하고 싶습니다. 할로겐화물의 존재는 전기화학적으로 신뢰할 수 있는 장치의 설계와 조립을 촉진하기 위해 특성화되어야 할 뿐입니다.
반대로 제조업체가 할로겐 프리 제품을 독점적으로 사용하기로 결정한 것은 환경적 고려에 따른 것입니다. 플럭스의 화학 성분 중 할로겐은 일반적으로 할로탄소이며, 할로겐 함유 플럭스 잔류물이 있는 어셈블리를 부적절하게 폐기할 경우 환경을 오염시킬 가능성이 있습니다. 할로겐 함유 플럭스는 전 세계적으로 매일 사용되고 있지만, 개별 기업은 이 문제를 완전히 피하기 위해 할로겐 함유 플럭스 사용을 거부하는 자체 규제를 선택할 수 있습니다. 전자제품에 모든 할로겐 함유 솔더 재료의 사용을 전면적으로 금지하는 정부 규정은 없습니다. 할로겐 함량을 특성화할 기술적 필요성이 없기 때문에 할로겐 테스트는 선택 사항입니다.
혼란스러운 부분
기술적으로 더 궁금한 점이 있는 분들을 위해 더 자세히 살펴볼 수 있습니다:
- In general chemistry, halogens are the elements in group 17 of the periodic table. A “halide” is any halogen-containing compound. Halides can be broken down into two main categories: ionically bonded and covalently bonded. In ionically bonded compounds, atoms with opposing charges (positive and negative) attract each other. If the negatively-charged atom is a halogen, it’s considered a “halide ion.” However, in the electronics industry and its standards, the term “halide” technically refers to a “halide ion.” The ion chromatography analysis does not detect the concentration of all halide species, only ionic halide species.
- Based on standard definitions, a flux could technically be classified as both “halide-free” and “halogen-containing.” Activators, one of the primary components of fluxes, are the chemicals that dissolve and remove oxides to enable soldering. Typically, activators are halocarbons or organic acids, and halocarbons are particularly effective at removing oxides. If a flux is formulated with halocarbons, halide ions can form within the flux due to side reactions. This is why many flux-containing products, notably solder paste, will be halide-containing if they are halogen-containing. However, it shouldn’t be assumed that a halide-free flux is also halogen-free.
- Using the same analytical method for halogen content, J-STD-004 defines flux residues as “low halogen” if Br ≤ 0.1% and Cl ≤ 0.1%. Yet, it’s uncommon to see a flux-containing material labeled as “low halogen.”
- A common question I get asked is, “What does the ‘HF’ in [product name] stand for?” Indium Corporation offers many solder pastes and fluxes with “HF” in the title (like Indium8.9HF, for example). The HF stands for halogen-free. However, not all halogen-free products have “HF” in their name. If a product is halogen-free, it will be noted on it’s product data sheet.
While this is a lot of information to digest, it’s important not to overthink it. For many assemblies, choosing between halide-free and halide-containing, or halogen-free and halogen-containing, is not going to make or break the device. There are many more factors to consider when selecting the optimal solder material. If you’re in the market for flux and solder, we encourage you to have a conversation with a member of our technical support team. We’ll be happy to discuss your project and help you navigate our portfolio of electronics assembly materials.
추가 읽기
J-STD-004에 의한 플럭스 특성 분석에 대한 자세한 내용은 이 문서를 참조하세요:
