根据牛津高阶词典解释
arbitration：the official process of settling an argument or a disagreement by sb who is not involved:Both sides in the dispute have agreed to go to arbitration.强调仲裁纠纷,对纠纷的仲裁用arbitration
sanction：（formal) official permission or approval for an action or a change:These changes will require the sanction of the court.强调批准,对行为的批准用sanction,该行为特点不是纠纷而是申请批准,仲裁的重点是行为可不可以执行而不是有没有纠纷.
当然根据实际情况,两个单词也可以重合使用,只要语境合适