Elon Musk, the chief executive of Tesla, said on Tuesday that China’s halt on exports of certain magnets was affecting his plans to build humanoid robots, in the clearest signal yet that China’s action is beginning to affect big American businesses.

特斯拉首席执行官埃隆·马斯克周二表示，中国暂停某些磁铁的出口影响了他制造人形机器人的计划。这是迄今中国的举措开始对美国大型企业产生影响的最明确信号。

China this month suspended exports to any country of so-called heavy rare earth metals and magnets made from them, as part of its retaliation for President Trump’s increases in tariffs on U.S. imports of Chinese goods. The Chinese government has stopped allowing shipments until it can devise an export license system.

中国本月全面暂停出口所谓的重稀土金属和由其制成的磁铁，作为对特朗普总统提高美国从中国进口商品关税的报复措施之一。在制定出口许可证制度之前，相关货物不予放行。

China produces the entire world’s supply of heavy rare earth metals, from ore mined in China and Myanmar, and 90 percent of magnets made with these metals. Japan produces the rest of the magnets, but uses raw materials from China.

中国掌控着全球重稀土金属的完整供应链——原料开采自中国与缅甸矿区，并占据该类稀土制磁铁90%的全球产量。日本虽生产剩余10%的磁铁，但原料仍依赖中国供应。

Rare earth magnets are used inside electric motors that need to fit in compact spaces. Robots have many small electric motors, typically one or more for each joint, that each require a magnet. The use of the heavy rare earths in most of these magnets keeps them from overheating and malfunctioning when motors are confined in small spaces.

稀土磁铁被用于需要安装在狭小空间的电动机内部。机器人身上搭载了许多小型电动机，通常每个关节都有一个或多个，每个电动机都需要一块磁铁。当马达被限制在狭小的空间时，大多数磁铁中使用的重稀土可以防止它们过热和出现故障。

去年在上海举行的世界人工智能大会期间，特斯拉的仿人机器人擎天柱在展台上。

Rare earth magnets are up to 15 times as powerful as conventional iron magnets of the same size. If traces of heavy rare earth metals are included in a magnet’s material, it can maintain its magnetic force even at temperatures that would boil water.

稀土磁铁的磁力可达同尺寸传统铁磁铁的15倍。如果磁铁材料中添加了微量的重稀土，即使处于水的沸点温度，也能保持磁力。

Mr. Musk said during Tesla’s earnings call on Tuesday that the company’s Optimus humanoid robots have electric motors in their arms that operate in a confined space and require the special magnets.

马斯克在周二的特斯拉财报电话会议上表示，该公司的“擎天柱”人形机器人手臂搭载的电动马达在密闭空间运行，必须使用这种特殊的磁铁。

“That’s more affected by the supply chain, by basically China requiring an export license to send out anywhere with magnets, so we’re working through that with China,” he said.

他说：“这更多受到供应链的影响，因为中国基本上要求出口磁铁到任何地方都要有出口许可证，所以我们正在与中国协商解决这个问题。”

A shortage in the supply of the magnets could slow the production of Optimus robots, Mr. Musk said.

马斯克说，磁铁供应短缺或拖延擎天柱机器人的生产速度。

Tesla is investing billions of dollars in the Optimus robots, which Mr. Musk has said will someday perform many daily functions. At an event last fall, he showed the robots serving drinks and unloading groceries from a car.

特斯拉在擎天柱机器人上投资了数十亿美元，马斯克曾表示，这些机器人有朝一日将执行许多日常任务。在去年秋天的一次活动中，他展示了这些机器人提供饮料以及从汽车上卸下杂货的场景。

Mr. Musk also said on the earnings call that he would reduce the time he spends as an adviser to President Trump to focus more on Tesla, which reported a drastic decline in profits.

马斯克还在财报电话会议上表示，他将减少作为特朗普总统顾问的时间，把更多精力放在特斯拉上，该公司的利润已大幅下滑。

Cars, factory robots, missiles, smart bombs, stealth fighters and many other products also require rare earth magnets made partly with heavy rare earth metals.

汽车、工厂机器人、导弹、智能炸弹、隐形战斗机和许多其他产品均需采用含重稀土元素的特种磁体。

Yang Jie, an export control lawyer at Huiye, a Shanghai law firm, said that China’s regulations call for the Ministry of Commerce to make decisions on export licenses within 45 working days of the announcement, which was on April 4. The ministry is allowed to take longer if it decides that licenses are relevant to national security.

上海汇业律师事务所的出口管制律师杨杰说，中国的法规要求商务部在4月4日发布公告后的45个工作日内就出口许可证做出决定。如果商务部认为许可证与国家安全有关，则可以延长决定时间。

Issuing export licenses for shipments to the United States could take much longer, given recent tensions between the two countries, he warned. “Six months for rare earth exports is my personal estimate of the fastest time — the actual time may be far more than six months,” he said.

他警告，鉴于两国最近的紧张关系，向美国发放出口许可证可能需要更长的时间。他说：“据此，稀土出口六个月是我个人预估的最快时间，实际时间可能远远超过六个月。”

Not all manufacturers of humanoid robots may be as affected as Tesla.

并非所有人形机器人制造商都像特斯拉一样受到影响。

Jonathan Hurst, the chief robot officer at Agility Robotics, another American maker of humanoid robots, said robots can be designed to minimize their need for magnets made with heavy rare earth metals.

乔纳森·赫斯特是另一家美国人形机器人制造商Agility Robotics的技术负责人，他说，可以在设计机器人时将它们对重稀土磁铁的需求降到最低。

Agility has designed its robots with slightly less human proportions than the Optimus robots. This provides more room for the electric motors, Mr. Hurst said. As a result, the motors in many of Agility’s robots may not overheat.

与擎天柱机器人相比，Agility的机器人不完全符合人体比例。赫斯特说，这为电动机提供了更大的空间。因此，Agility的许多机器人的马达可能不会过热。

Since the April 4 ban, China’s customs agents have been checking exports carefully to make sure that no magnets with heavy rare earths are allowed to leave the country, industry executives said.

行业高管表示，自4月4日的禁令以来，中国海关一直在严查出口货物，确保含有重稀土的磁铁不会出境。